From 5f1da6956c1eaa4ff3d38e14b3ef3516d55f2bdd Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Wed, 29 Jul 2020 15:53:54 +0100
Subject: [PATCH 01/17] Consistant naming in function comments

---
 workers/unity/Packages/io.improbable.worker.sdk/CIO.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs b/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs
index dfabb649d9..4639c69908 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs
@@ -142,7 +142,7 @@ public enum OpenMode
          * Returns the actual number of bytes read. This may be less than the given length iff the stream
          * has less data than the requested amount.
          *
-         * Returns -1 on error. Call StreamGetLastError() to get the associated error message.
+         * Returns -1 on error. Call StreamGetLastError to get the associated error message.
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_Stream_Peek")]
@@ -155,7 +155,7 @@ public enum OpenMode
          * has advanced. This may be less than the given length iff the stream has less data than the
          * requested amount.
          *
-         * Returns -1 on error. Call StreamGetLastError() to get the associated error message.
+         * Returns -1 on error. Call StreamGetLastError to get the associated error message.
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_Stream_Ignore")]

From 86b472e0270957c13d8a3fc78168f5cef54ba495 Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Wed, 29 Jul 2020 15:54:10 +0100
Subject: [PATCH 02/17] Add IOStream native wrapper

---
 .../io.improbable.worker.sdk/IOStream.cs      | 111 ++++++++++++++++++
 .../io.improbable.worker.sdk/IOStream.cs.meta |   3 +
 2 files changed, 114 insertions(+)
 create mode 100644 workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
 create mode 100644 workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs.meta

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
new file mode 100644
index 0000000000..dbea548e1f
--- /dev/null
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
@@ -0,0 +1,111 @@
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+using Improbable.Worker.CInterop.Internal;
+
+namespace Packages.io.improbable.worker.sdk
+{
+    public unsafe class IOStream : IDisposable
+    {
+        private readonly CIO.StreamHandle stream;
+
+        private IOStream(CIO.StreamHandle stream)
+        {
+            this.stream = stream;
+        }
+
+        /// <inheritdoc cref="IDisposable"/>
+        public void Dispose()
+        {
+            stream.Dispose();
+        }
+
+        public static IOStream CreateRingBufferStream(uint capacity)
+        {
+            return new IOStream(CIO.CreateRingBufferStream(capacity));
+        }
+
+        public static IOStream CreateFileStream(string fileName)
+        {
+            fixed (byte* fileNameBytes = ApiInterop.ToUtf8Cstr(fileName))
+            {
+                return new IOStream(CIO.CreateFileStream(fileNameBytes, CIO.OpenMode.OpenModeDefault));
+            }
+        }
+
+        public void Write(byte[] data)
+        {
+            // Maybe use StreamGetRemainingWriteCapacityBytes to prevent attempting to write to the stream if
+            // sizeof(data) > remaining capacity
+
+            var remainingCapacity = CIO.StreamGetRemainingWriteCapacityBytes(stream);
+            if (remainingCapacity < data.Length)
+            {
+                throw new IOException("Not enough stream capacity to write data.");
+            }
+
+            fixed (byte* dataToWrite = data)
+            {
+                var bytesWritten = CIO.StreamWrite(stream, dataToWrite, 1);
+
+                if (bytesWritten == -1)
+                {
+                    // The Stream write failed, check the error message
+                    var rawError = CIO.StreamGetLastError(stream);
+                    throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
+                }
+
+                if (bytesWritten != data.Length)
+                {
+                    // Check that the number of bytes we tried to write was the number of bytes written
+                    throw new IOException("Failed to write all data to stream.");
+                }
+            }
+        }
+
+        public byte[] Read(uint bytesToRead)
+        {
+            var b = new byte[bytesToRead];
+            var c = GCHandle.Alloc(b, GCHandleType.Pinned);
+            var bytesRead = CIO.StreamRead(stream, (byte*) c.AddrOfPinnedObject(), bytesToRead);
+
+            if (bytesRead == -1)
+            {
+                var rawError = CIO.StreamGetLastError(stream);
+                throw new Exception(ApiInterop.FromUtf8Cstr(rawError));
+            }
+
+            if (bytesRead != bytesToRead)
+            {
+                throw new Exception($"Failed to read {bytesToRead} bytes, only read ${bytesRead}.");
+            }
+
+            return c.Target as byte[];
+        }
+
+        public byte[] Peek(uint bytes)
+        {
+            var b = new byte[bytes];
+            var c = GCHandle.Alloc(b, GCHandleType.Pinned);
+            var bytesPeeked = CIO.StreamPeek(stream, (byte*) c.AddrOfPinnedObject(), bytes);
+
+            if (bytesPeeked == -1)
+            {
+                var rawError = CIO.StreamGetLastError(stream);
+                throw new Exception(ApiInterop.FromUtf8Cstr(rawError));
+            }
+
+            if (bytesPeeked != bytes)
+            {
+                throw new Exception($"Failed to read {bytes} bytes, only read ${bytes}.");
+            }
+
+            return c.Target as byte[];
+        }
+
+        public void Ignore(uint bytesToIgnore)
+        {
+            CIO.StreamIgnore(stream, bytesToIgnore);
+        }
+    }
+}
diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs.meta b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs.meta
new file mode 100644
index 0000000000..61e529facb
--- /dev/null
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs.meta
@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: b0e0fbfec8ff4c5e99a8b505c9ccb705
+timeCreated: 1595944475
\ No newline at end of file

From 8ede688736442e32836f35cb7ffa7f9ae715cd3a Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Wed, 29 Jul 2020 15:54:20 +0100
Subject: [PATCH 03/17] Add IOStorage native wrapper

---
 .../io.improbable.worker.sdk/IOStorage.cs     | 28 +++++++++++++++++++
 .../IOStorage.cs.meta                         |  3 ++
 2 files changed, 31 insertions(+)
 create mode 100644 workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
 create mode 100644 workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs.meta

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
new file mode 100644
index 0000000000..fb8cd3d7c6
--- /dev/null
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
@@ -0,0 +1,28 @@
+using System;
+using System.Runtime.InteropServices;
+using Improbable.Worker.CInterop.Internal;
+using Packages.io.improbable.worker.sdk;
+
+namespace Improbable.Worker.CInterop
+{
+    public class IOStorage : IDisposable
+    {
+        private readonly CIO.StorageHandle storage;
+
+        public IOStorage()
+        {
+            storage = CIO.StorageCreate();
+        }
+
+        /// <inheritdoc cref="IDisposable"/>
+        public void Dispose()
+        {
+            storage.Dispose();
+        }
+
+        public void Clear()
+        {
+            CIO.StorageClear(storage);
+        }
+    }
+}
diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs.meta b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs.meta
new file mode 100644
index 0000000000..e9e14df0a1
--- /dev/null
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs.meta
@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: e50ee44109544e7d8d9d06fe8c1243f2
+timeCreated: 1595864556
\ No newline at end of file

From 5ab2acfd0dd40a3153c06b5c460b9b4b55b1591b Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Wed, 29 Jul 2020 16:42:09 +0100
Subject: [PATCH 04/17] Fix naming of Storage/Stream handles in params

---
 .../Packages/io.improbable.worker.sdk/CIO.cs  | 24 +++++++++----------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs b/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs
index 4639c69908..5fef75ff2c 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs
@@ -10,7 +10,7 @@ namespace Improbable.Worker.CInterop.Internal
 {
     internal unsafe class CIO
     {
-        public class Storage : CptrHandle
+        public class StorageHandle : CptrHandle
         {
             protected override bool ReleaseHandle()
             {
@@ -19,7 +19,7 @@ protected override bool ReleaseHandle()
             }
         }
 
-        public class Stream : CptrHandle
+        public class StreamHandle : CptrHandle
         {
             protected override bool ReleaseHandle()
             {
@@ -45,7 +45,7 @@ public enum OpenMode
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_Storage_Create")]
-        public static extern Storage StorageCreate();
+        public static extern StorageHandle StorageCreate();
 
         /* Destroys the trace storage. */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
@@ -61,7 +61,7 @@ public enum OpenMode
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_Storage_Clear")]
-        public static extern void StorageClear(IntPtr storage);
+        public static extern void StorageClear(StorageHandle storage);
 
         /**
          * Creates an I/O stream implemented as a ring buffer.
@@ -77,7 +77,7 @@ public enum OpenMode
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_CreateRingBufferStream")]
-        public static extern Stream CreateRingBufferStream(Uint32 capacityBytes);
+        public static extern StreamHandle CreateRingBufferStream(Uint32 capacityBytes);
 
         /**
          * Creates an I/O stream implemented as a read/write file.
@@ -94,7 +94,7 @@ public enum OpenMode
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_CreateFileStream")]
-        public static extern Stream CreateFileStream(Char* filename, OpenMode openMode);
+        public static extern StreamHandle CreateFileStream(Char* filename, OpenMode openMode);
 
         /* Destroys the I/O stream. */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
@@ -111,7 +111,7 @@ public enum OpenMode
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_Stream_Write")]
-        public static extern Int64 StreamWrite(Stream stream, Uint8* bytes, Uint32 length);
+        public static extern Int64 StreamWrite(StreamHandle stream, Uint8* bytes, Uint32 length);
 
         /**
          * Gets the remaining write capacity in bytes.
@@ -121,7 +121,7 @@ public enum OpenMode
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_Stream_GetRemainingWriteCapacityBytes")]
-        public static extern Uint32 StreamGetRemainingWriteCapacityBytes(Stream stream);
+        public static extern Uint32 StreamGetRemainingWriteCapacityBytes(StreamHandle stream);
 
         /**
          * Reads as much of the stream's data as possible into the given buffer.
@@ -133,7 +133,7 @@ public enum OpenMode
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_Stream_Read")]
-        public static extern Uint64 StreamRead(Stream stream, Uint8* bytes, Uint32 length);
+        public static extern Uint64 StreamRead(StreamHandle stream, Uint8* bytes, Uint32 length);
 
         /**
          * Reads as much of the stream's data as possible into the given buffer without advancing the read
@@ -146,7 +146,7 @@ public enum OpenMode
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_Stream_Peek")]
-        public static extern Int64 StreamPeek(Stream stream, Uint8* bytes, Uint32 length);
+        public static extern Int64 StreamPeek(StreamHandle stream, Uint8* bytes, Uint32 length);
 
         /**
          * Extracts the given number of bytes from the stream and discards them.
@@ -159,7 +159,7 @@ public enum OpenMode
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_Stream_Ignore")]
-        public static extern Int64 StreamIgnore(Stream stream, Uint32 length);
+        public static extern Int64 StreamIgnore(StreamHandle stream, Uint32 length);
 
         /**
          * Returns the last error which occurred during an API call on this stream. Returns nullptr if no
@@ -167,6 +167,6 @@ public enum OpenMode
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_Stream_GetLastError")]
-        public static extern Char* StreamGetLastError(Stream stream);
+        public static extern Char* StreamGetLastError(StreamHandle stream);
     }
 }

From d24a3e8de5c014ee32378e45524cd42b8e237938 Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Wed, 29 Jul 2020 16:53:11 +0100
Subject: [PATCH 05/17] Consistant naming for Stream/Storage handles

---
 .../Packages/io.improbable.worker.sdk/CEventTrace.cs      | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/CEventTrace.cs b/workers/unity/Packages/io.improbable.worker.sdk/CEventTrace.cs
index 337d7e32f3..b35e12f852 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/CEventTrace.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/CEventTrace.cs
@@ -278,7 +278,7 @@ public struct EventTracerParameters
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Trace_Item_Create")]
-        public static extern Item* ItemCreate(CIO.Storage storage, Item* item);
+        public static extern Item* ItemCreate(CIO.StorageHandle storage, Item* item);
 
         /**
          * Returns a pointer to a thread-local trace item.
@@ -320,7 +320,7 @@ public struct EventTracerParameters
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Trace_SerializeItemToStream")]
-        public static extern Int8 SerializeItemToStream(CIO.Stream stream, Item* item, Uint32 size);
+        public static extern Int8 SerializeItemToStream(CIO.StreamHandle stream, Item* item, Uint32 size);
 
         /**
          * Get the serialized size, in bytes, of the next serialized trace item to be read from the stream.
@@ -332,7 +332,7 @@ public struct EventTracerParameters
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Trace_GetNextSerializedItemSize")]
-        public static extern Uint32 GetNextSerializedItemSize(CIO.Stream stream);
+        public static extern Uint32 GetNextSerializedItemSize(CIO.StreamHandle stream);
 
         /**
          * Deserialize the next trace item from the stream.
@@ -356,7 +356,7 @@ public struct EventTracerParameters
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Trace_DeserializeItemFromStream")]
-        public static extern Int8 DeserializeItemFromStream(CIO.Stream stream, Item* item, Uint32 size);
+        public static extern Int8 DeserializeItemFromStream(CIO.StreamHandle stream, Item* item, Uint32 size);
 
         /**
          * Returns the last error which occurred during a trace API method call. Returns nullptr if no

From fbd7af708c099719ca60c0377b304b808a343f0c Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Thu, 30 Jul 2020 16:52:40 +0100
Subject: [PATCH 06/17] Code cleanup

---
 workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs | 2 --
 workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs  | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
index fb8cd3d7c6..ec2bacb4d6 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
@@ -1,7 +1,5 @@
 using System;
-using System.Runtime.InteropServices;
 using Improbable.Worker.CInterop.Internal;
-using Packages.io.improbable.worker.sdk;
 
 namespace Improbable.Worker.CInterop
 {
diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
index dbea548e1f..73fc00e6c9 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
@@ -3,7 +3,7 @@
 using System.Runtime.InteropServices;
 using Improbable.Worker.CInterop.Internal;
 
-namespace Packages.io.improbable.worker.sdk
+namespace Improbable.Worker.CInterop
 {
     public unsafe class IOStream : IDisposable
     {

From 2b1fec92541a957e778eabec5ee43c2bdcec0ec6 Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Thu, 30 Jul 2020 16:52:58 +0100
Subject: [PATCH 07/17] Fix return type for CIO StreamRead

---
 workers/unity/Packages/io.improbable.worker.sdk/CIO.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs b/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs
index 5fef75ff2c..2bc19c2605 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/CIO.cs
@@ -133,7 +133,7 @@ public enum OpenMode
          */
         [DllImport(Constants.WorkerLibrary, CallingConvention = CallingConvention.Cdecl,
             EntryPoint = "Io_Stream_Read")]
-        public static extern Uint64 StreamRead(StreamHandle stream, Uint8* bytes, Uint32 length);
+        public static extern Int64 StreamRead(StreamHandle stream, Uint8* bytes, Uint32 length);
 
         /**
          * Reads as much of the stream's data as possible into the given buffer without advancing the read

From 152c85af4920674a1327a06ee13d4f7666b07760 Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Thu, 30 Jul 2020 17:20:03 +0100
Subject: [PATCH 08/17] Variable naming in IOStream, add error handling

---
 .../io.improbable.worker.sdk/IOStream.cs      | 40 +++++++++++--------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
index 73fc00e6c9..a703c6e00c 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
@@ -35,9 +35,6 @@ public static IOStream CreateFileStream(string fileName)
 
         public void Write(byte[] data)
         {
-            // Maybe use StreamGetRemainingWriteCapacityBytes to prevent attempting to write to the stream if
-            // sizeof(data) > remaining capacity
-
             var remainingCapacity = CIO.StreamGetRemainingWriteCapacityBytes(stream);
             if (remainingCapacity < data.Length)
             {
@@ -65,47 +62,58 @@ public void Write(byte[] data)
 
         public byte[] Read(uint bytesToRead)
         {
-            var b = new byte[bytesToRead];
-            var c = GCHandle.Alloc(b, GCHandleType.Pinned);
-            var bytesRead = CIO.StreamRead(stream, (byte*) c.AddrOfPinnedObject(), bytesToRead);
+            var streamData = new byte[bytesToRead];
+            var dataHandle = GCHandle.Alloc(streamData, GCHandleType.Pinned);
+            var bytesRead = CIO.StreamRead(stream, (byte*) dataHandle.AddrOfPinnedObject(), bytesToRead);
 
             if (bytesRead == -1)
             {
                 var rawError = CIO.StreamGetLastError(stream);
-                throw new Exception(ApiInterop.FromUtf8Cstr(rawError));
+                throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
             }
 
             if (bytesRead != bytesToRead)
             {
-                throw new Exception($"Failed to read {bytesToRead} bytes, only read ${bytesRead}.");
+                throw new IOException($"Failed to read {bytesToRead} bytes, only read {bytesRead}.");
             }
 
-            return c.Target as byte[];
+            return dataHandle.Target as byte[];
         }
 
         public byte[] Peek(uint bytes)
         {
-            var b = new byte[bytes];
-            var c = GCHandle.Alloc(b, GCHandleType.Pinned);
-            var bytesPeeked = CIO.StreamPeek(stream, (byte*) c.AddrOfPinnedObject(), bytes);
+            var streamData = new byte[bytes];
+            var dataHandle = GCHandle.Alloc(streamData, GCHandleType.Pinned);
+            var bytesPeeked = CIO.StreamPeek(stream, (byte*) dataHandle.AddrOfPinnedObject(), bytes);
 
             if (bytesPeeked == -1)
             {
                 var rawError = CIO.StreamGetLastError(stream);
-                throw new Exception(ApiInterop.FromUtf8Cstr(rawError));
+                throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
             }
 
             if (bytesPeeked != bytes)
             {
-                throw new Exception($"Failed to read {bytes} bytes, only read ${bytes}.");
+                throw new IOException($"Failed to read {bytes} bytes, only read {bytes}.");
             }
 
-            return c.Target as byte[];
+            return dataHandle.Target as byte[];
         }
 
         public void Ignore(uint bytesToIgnore)
         {
-            CIO.StreamIgnore(stream, bytesToIgnore);
+            var bytesIgnored = CIO.StreamIgnore(stream, bytesToIgnore);
+
+            if (bytesIgnored == -1)
+            {
+                var rawError = CIO.StreamGetLastError(stream);
+                throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
+            }
+
+            if (bytesIgnored != bytesToIgnore)
+            {
+                throw new IOException($"Failed to ignore {bytesToIgnore} bytes, only ignored {bytesToIgnore}.");
+            }
         }
     }
 }

From bbe294e3e37a324ce1204da6c67a78bc32e2b4b4 Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Thu, 30 Jul 2020 17:22:43 +0100
Subject: [PATCH 09/17] Add changelog entry

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 17fce49b94..dc28ff6058 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@
 ### Internal
 
 - Added C# bindings for C Event Tracing API. [#1440](https://github.com/spatialos/gdk-for-unity/pull/1440)
+- Added native classes for IO operations in Event Tracing API. [#1444](https://github.com/spatialos/gdk-for-unity/pull/1444)
 
 ## `0.3.9` - 2020-07-24
 

From 445390cf016f1987623ccd89692a25e18ca6dd9d Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Mon, 3 Aug 2020 11:02:02 +0100
Subject: [PATCH 10/17] Add GC suppress finialize call to dispose method

---
 workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs | 1 +
 workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs  | 1 +
 2 files changed, 2 insertions(+)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
index ec2bacb4d6..986f83daa1 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
@@ -16,6 +16,7 @@ public IOStorage()
         public void Dispose()
         {
             storage.Dispose();
+            GC.SuppressFinalize(this);
         }
 
         public void Clear()
diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
index a703c6e00c..b6129752f1 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
@@ -18,6 +18,7 @@ private IOStream(CIO.StreamHandle stream)
         public void Dispose()
         {
             stream.Dispose();
+            GC.SuppressFinalize(this);
         }
 
         public static IOStream CreateRingBufferStream(uint capacity)

From 297ebf5d66dd0a45918e3dedcc4fd4ceedf6d70d Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Mon, 3 Aug 2020 14:25:45 +0100
Subject: [PATCH 11/17] Change from throwing errors to return byte amounts

Removed reference to internal namespace enum
---
 .../io.improbable.worker.sdk/IOStream.cs      | 101 ++++++++++--------
 1 file changed, 58 insertions(+), 43 deletions(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
index b6129752f1..2056f383c3 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
@@ -5,9 +5,15 @@
 
 namespace Improbable.Worker.CInterop
 {
-    public unsafe class IOStream : IDisposable
+    public enum OpenMode
     {
-        private readonly CIO.StreamHandle stream;
+        /* Opens the stream in the default mode. */
+        OpenModeDefault = 0x00,
+    }
+
+    public sealed unsafe class IOStream : IDisposable
+    {
+        public readonly CIO.StreamHandle stream;
 
         private IOStream(CIO.StreamHandle stream)
         {
@@ -26,15 +32,15 @@ public static IOStream CreateRingBufferStream(uint capacity)
             return new IOStream(CIO.CreateRingBufferStream(capacity));
         }
 
-        public static IOStream CreateFileStream(string fileName)
+        public static IOStream CreateFileStream(string fileName, OpenMode openMode)
         {
             fixed (byte* fileNameBytes = ApiInterop.ToUtf8Cstr(fileName))
             {
-                return new IOStream(CIO.CreateFileStream(fileNameBytes, CIO.OpenMode.OpenModeDefault));
+                return new IOStream(CIO.CreateFileStream(fileNameBytes, (CIO.OpenMode) openMode));
             }
         }
 
-        public void Write(byte[] data)
+        public long Write(byte[] data)
         {
             var remainingCapacity = CIO.StreamGetRemainingWriteCapacityBytes(stream);
             if (remainingCapacity < data.Length)
@@ -42,79 +48,88 @@ public void Write(byte[] data)
                 throw new IOException("Not enough stream capacity to write data.");
             }
 
+            var bytesWritten = 0L;
             fixed (byte* dataToWrite = data)
             {
-                var bytesWritten = CIO.StreamWrite(stream, dataToWrite, 1);
-
-                if (bytesWritten == -1)
-                {
-                    // The Stream write failed, check the error message
-                    var rawError = CIO.StreamGetLastError(stream);
-                    throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
-                }
-
-                if (bytesWritten != data.Length)
-                {
-                    // Check that the number of bytes we tried to write was the number of bytes written
-                    throw new IOException("Failed to write all data to stream.");
-                }
+                bytesWritten = CIO.StreamWrite(stream, dataToWrite, 1);
             }
+
+            if (bytesWritten != -1)
+            {
+                return bytesWritten;
+            }
+
+            var rawError = CIO.StreamGetLastError(stream);
+            throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
         }
 
-        public byte[] Read(uint bytesToRead)
+        public (byte[], long) Read(uint bytesToRead)
         {
             var streamData = new byte[bytesToRead];
-            var dataHandle = GCHandle.Alloc(streamData, GCHandleType.Pinned);
-            var bytesRead = CIO.StreamRead(stream, (byte*) dataHandle.AddrOfPinnedObject(), bytesToRead);
 
-            if (bytesRead == -1)
+            var bytesRead = 0L;
+            fixed (byte* streamDataPointer = streamData)
+            {
+                bytesRead = CIO.StreamRead(stream, streamDataPointer, bytesToRead);
+            }
+
+            if (bytesRead != -1)
             {
-                var rawError = CIO.StreamGetLastError(stream);
-                throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
+                return (streamData, bytesRead);
             }
 
-            if (bytesRead != bytesToRead)
+            var rawError = CIO.StreamGetLastError(stream);
+            throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
+        }
+
+        public long Read(byte[] streamData)
+        {
+            var bytesToRead = (uint) streamData.Length;
+            var bytesRead = 0L;
+            fixed (byte* streamDataPointer = streamData)
             {
-                throw new IOException($"Failed to read {bytesToRead} bytes, only read {bytesRead}.");
+                bytesRead = CIO.StreamRead(stream, streamDataPointer, bytesToRead);
             }
 
-            return dataHandle.Target as byte[];
+            if (bytesRead != -1)
+            {
+                return bytesRead;
+            }
+
+            var rawError = CIO.StreamGetLastError(stream);
+            throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
         }
 
         public byte[] Peek(uint bytes)
         {
             var streamData = new byte[bytes];
-            var dataHandle = GCHandle.Alloc(streamData, GCHandleType.Pinned);
-            var bytesPeeked = CIO.StreamPeek(stream, (byte*) dataHandle.AddrOfPinnedObject(), bytes);
 
-            if (bytesPeeked == -1)
+            var bytesPeeked = 0L;
+            fixed (byte* streamDataPointer = streamData)
             {
-                var rawError = CIO.StreamGetLastError(stream);
-                throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
+                bytesPeeked = CIO.StreamPeek(stream, streamDataPointer, bytes);
             }
 
-            if (bytesPeeked != bytes)
+            if (bytesPeeked != -1)
             {
-                throw new IOException($"Failed to read {bytes} bytes, only read {bytes}.");
+                return streamData;
             }
 
-            return dataHandle.Target as byte[];
+            var rawError = CIO.StreamGetLastError(stream);
+            throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
         }
 
         public void Ignore(uint bytesToIgnore)
         {
             var bytesIgnored = CIO.StreamIgnore(stream, bytesToIgnore);
 
-            if (bytesIgnored == -1)
+            if (bytesIgnored != -1)
             {
-                var rawError = CIO.StreamGetLastError(stream);
-                throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
+                return;
             }
 
-            if (bytesIgnored != bytesToIgnore)
-            {
-                throw new IOException($"Failed to ignore {bytesToIgnore} bytes, only ignored {bytesToIgnore}.");
-            }
+            var rawError = CIO.StreamGetLastError(stream);
+            throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
         }
     }
 }

From fe76a7f011bd8bd94dbe66e36efa135a47db0008 Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Mon, 3 Aug 2020 14:52:25 +0100
Subject: [PATCH 12/17] Fix IO stream scope for StreamHandle

---
 workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
index 2056f383c3..c750f071fa 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
@@ -13,7 +13,7 @@ public enum OpenMode
 
     public sealed unsafe class IOStream : IDisposable
     {
-        public readonly CIO.StreamHandle stream;
+        private readonly CIO.StreamHandle stream;
 
         private IOStream(CIO.StreamHandle stream)
         {

From fe6c03b0d6756b15516d854df6366784720aae1e Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Mon, 3 Aug 2020 15:08:12 +0100
Subject: [PATCH 13/17] Add sealed to IOStorage class

---
 workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
index 986f83daa1..a64e3026c8 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
@@ -3,7 +3,7 @@
 
 namespace Improbable.Worker.CInterop
 {
-    public class IOStorage : IDisposable
+    public sealed class IOStorage : IDisposable
     {
         private readonly CIO.StorageHandle storage;
 

From 56a343a163e66a97368e5c5e3004d9c19888fa92 Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Mon, 3 Aug 2020 17:10:51 +0100
Subject: [PATCH 14/17] Remove GC SuppressFinalize call

---
 workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs | 1 -
 workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs  | 1 -
 2 files changed, 2 deletions(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
index a64e3026c8..e2f58019f0 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStorage.cs
@@ -16,7 +16,6 @@ public IOStorage()
         public void Dispose()
         {
             storage.Dispose();
-            GC.SuppressFinalize(this);
         }
 
         public void Clear()
diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
index c750f071fa..7645678c46 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
@@ -24,7 +24,6 @@ private IOStream(CIO.StreamHandle stream)
         public void Dispose()
         {
             stream.Dispose();
-            GC.SuppressFinalize(this);
         }
 
         public static IOStream CreateRingBufferStream(uint capacity)

From 423dc22d63dd847c5d15b1533b4b50361d5dd34d Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Mon, 3 Aug 2020 17:49:25 +0100
Subject: [PATCH 15/17] Switch from tuple return to out var for IO read

---
 .../unity/Packages/io.improbable.worker.sdk/IOStream.cs    | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
index 7645678c46..fe9beca601 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
@@ -1,6 +1,5 @@
 using System;
 using System.IO;
-using System.Runtime.InteropServices;
 using Improbable.Worker.CInterop.Internal;
 
 namespace Improbable.Worker.CInterop
@@ -62,9 +61,9 @@ public long Write(byte[] data)
             throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
         }
 
-        public (byte[], long) Read(uint bytesToRead)
+        public long Read(uint bytesToRead, out byte[] streamData)
         {
-            var streamData = new byte[bytesToRead];
+            streamData = new byte[bytesToRead];
 
             var bytesRead = 0L;
             fixed (byte* streamDataPointer = streamData)
@@ -74,7 +73,7 @@ public long Write(byte[] data)
 
             if (bytesRead != -1)
             {
-                return (streamData, bytesRead);
+                return bytesRead;
             }
 
             var rawError = CIO.StreamGetLastError(stream);

From b7409d6a0d0139604201d56ca1da0ed7b80ed4d9 Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Tue, 4 Aug 2020 13:55:09 +0100
Subject: [PATCH 16/17] Add error handling to check if stream closed

---
 .../io.improbable.worker.sdk/IOStream.cs      | 37 +++++++++++++++----
 1 file changed, 30 insertions(+), 7 deletions(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
index fe9beca601..d8c618ba97 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
@@ -40,10 +40,12 @@ public static IOStream CreateFileStream(string fileName, OpenMode openMode)
 
         public long Write(byte[] data)
         {
+            CheckIfStreamClosed();
+
             var remainingCapacity = CIO.StreamGetRemainingWriteCapacityBytes(stream);
             if (remainingCapacity < data.Length)
             {
-                throw new IOException("Not enough stream capacity to write data.");
+                throw new NotSupportedException("Not enough stream capacity to write data.");
             }
 
             var bytesWritten = 0L;
@@ -63,6 +65,8 @@ public long Write(byte[] data)
 
         public long Read(uint bytesToRead, out byte[] streamData)
         {
+            CheckIfStreamClosed();
+
             streamData = new byte[bytesToRead];
 
             var bytesRead = 0L;
@@ -82,6 +86,8 @@ public long Read(uint bytesToRead, out byte[] streamData)
 
         public long Read(byte[] streamData)
         {
+            CheckIfStreamClosed();
+
             var bytesToRead = (uint) streamData.Length;
             var bytesRead = 0L;
             fixed (byte* streamDataPointer = streamData)
@@ -98,36 +104,53 @@ public long Read(byte[] streamData)
             throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
         }
 
-        public byte[] Peek(uint bytes)
+        public long Peek(uint bytesToPeek, out byte[] streamData)
         {
-            var streamData = new byte[bytes];
+            CheckIfStreamClosed();
+
+            streamData = new byte[bytesToPeek];
 
             var bytesPeeked = 0L;
             fixed (byte* streamDataPointer = streamData)
             {
-                bytesPeeked = CIO.StreamPeek(stream, streamDataPointer, bytes);
+                bytesPeeked = CIO.StreamPeek(stream, streamDataPointer, bytesToPeek);
             }
 
             if (bytesPeeked != -1)
             {
-                return streamData;
+                return bytesPeeked;
             }
 
             var rawError = CIO.StreamGetLastError(stream);
             throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
         }
 
-        public void Ignore(uint bytesToIgnore)
+        public long Ignore(uint bytesToIgnore)
         {
+            CheckIfStreamClosed();
+
             var bytesIgnored = CIO.StreamIgnore(stream, bytesToIgnore);
 
             if (bytesIgnored != -1)
             {
-                return;
+                return bytesIgnored;
             }
 
             var rawError = CIO.StreamGetLastError(stream);
             throw new IOException(ApiInterop.FromUtf8Cstr(rawError));
         }
+
+        public uint GetRemainingCapacity()
+        {
+            return CIO.StreamGetRemainingWriteCapacityBytes(stream);
+        }
+
+        private void CheckIfStreamClosed()
+        {
+            if (stream.IsClosed)
+            {
+                throw new ObjectDisposedException("Cannot access a disposed object.");
+            }
+        }
     }
 }

From bc9adbdd150b8ce4c4d1129884701c95047ca54a Mon Sep 17 00:00:00 2001
From: Sean Parker <seanparker@improbable.io>
Date: Tue, 4 Aug 2020 14:14:40 +0100
Subject: [PATCH 17/17] Clarify function name if stream is closed

---
 .../Packages/io.improbable.worker.sdk/IOStream.cs    | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
index d8c618ba97..5a48eada96 100644
--- a/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
+++ b/workers/unity/Packages/io.improbable.worker.sdk/IOStream.cs
@@ -40,7 +40,7 @@ public static IOStream CreateFileStream(string fileName, OpenMode openMode)
 
         public long Write(byte[] data)
         {
-            CheckIfStreamClosed();
+            ThrowIfStreamClosed();
 
             var remainingCapacity = CIO.StreamGetRemainingWriteCapacityBytes(stream);
             if (remainingCapacity < data.Length)
@@ -65,7 +65,7 @@ public long Write(byte[] data)
 
         public long Read(uint bytesToRead, out byte[] streamData)
         {
-            CheckIfStreamClosed();
+            ThrowIfStreamClosed();
 
             streamData = new byte[bytesToRead];
 
@@ -86,7 +86,7 @@ public long Read(uint bytesToRead, out byte[] streamData)
 
         public long Read(byte[] streamData)
         {
-            CheckIfStreamClosed();
+            ThrowIfStreamClosed();
 
             var bytesToRead = (uint) streamData.Length;
             var bytesRead = 0L;
@@ -106,7 +106,7 @@ public long Read(byte[] streamData)
 
         public long Peek(uint bytesToPeek, out byte[] streamData)
         {
-            CheckIfStreamClosed();
+            ThrowIfStreamClosed();
 
             streamData = new byte[bytesToPeek];
 
@@ -127,7 +127,7 @@ public long Peek(uint bytesToPeek, out byte[] streamData)
 
         public long Ignore(uint bytesToIgnore)
         {
-            CheckIfStreamClosed();
+            ThrowIfStreamClosed();
 
             var bytesIgnored = CIO.StreamIgnore(stream, bytesToIgnore);
 
@@ -145,7 +145,7 @@ public uint GetRemainingCapacity()
             return CIO.StreamGetRemainingWriteCapacityBytes(stream);
         }
 
-        private void CheckIfStreamClosed()
+        private void ThrowIfStreamClosed()
         {
             if (stream.IsClosed)
             {