diff --git a/SteamKit2/SteamKit2/Networking/Steam3/UdpConnection.cs b/SteamKit2/SteamKit2/Networking/Steam3/UdpConnection.cs
index 7f85b4454..7d8a4eb5d 100644
--- a/SteamKit2/SteamKit2/Networking/Steam3/UdpConnection.cs
+++ b/SteamKit2/SteamKit2/Networking/Steam3/UdpConnection.cs
@@ -7,7 +7,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Net;
 using System.Net.Sockets;
@@ -87,8 +86,8 @@ private enum State
         /// </summary>
         private uint inSeqHandled;
 
-        [NotNull] private List<UdpPacket>? outPackets;
-        [NotNull] private Dictionary<uint, UdpPacket>? inPackets;
+        private List<UdpPacket> outPackets;
+        private Dictionary<uint, UdpPacket> inPackets;
 
         private ILogContext log;
 
@@ -102,6 +101,9 @@ public UdpConnection(ILogContext log)
             sock.Bind(localEndPoint);
 
             state = (int)State.Disconnected;
+
+            outPackets = new List<UdpPacket>();
+            inPackets = new Dictionary<uint, UdpPacket>();
         }
 
         public event EventHandler<NetMsgEventArgs>? NetMsgReceived;
@@ -121,8 +123,8 @@ public UdpConnection(ILogContext log)
         /// <param name="timeout">Timeout in milliseconds</param>
         public void Connect(EndPoint endPoint, int timeout)
         {
-            outPackets = new List<UdpPacket>();
-            inPackets = new Dictionary<uint, UdpPacket>();
+            outPackets.Clear();
+            inPackets.Clear();
 
             CurrentEndPoint = null;
             remoteConnId = 0;
diff --git a/SteamKit2/SteamKit2/Networking/Steam3/UdpPacket.cs b/SteamKit2/SteamKit2/Networking/Steam3/UdpPacket.cs
index 3d649a8bd..4b865f27a 100644
--- a/SteamKit2/SteamKit2/Networking/Steam3/UdpPacket.cs
+++ b/SteamKit2/SteamKit2/Networking/Steam3/UdpPacket.cs
@@ -53,13 +53,17 @@ public UdpPacket(MemoryStream ms)
             }
             catch ( Exception )
             {
+                Payload = new MemoryStream();
                 return;
             }
 
             if ( this.Header.Magic != UdpHeader.MAGIC )
+            {
+                Payload = new MemoryStream();
                 return;
+            }
 
-            SetPayload(ms, Header.PayloadSize);
+            Payload = GetPayloadAndUpdateHeader( ms, Header.PayloadSize, Header );
         }
 
         /// <summary>
@@ -121,16 +125,22 @@ public void SetPayload(MemoryStream ms)
         /// <param name="ms">The payload.</param>
         /// <param name="length">The length.</param>
         public void SetPayload(MemoryStream ms, long length)
+        {
+            Payload = GetPayloadAndUpdateHeader( ms, length, Header );
+        }
+
+        static MemoryStream GetPayloadAndUpdateHeader(MemoryStream ms, long length, UdpHeader header)
         {
             if ( length > MAX_PAYLOAD )
-                throw new ArgumentException("Payload length exceeds 0x4DC maximum");
+                throw new ArgumentException( "Payload length exceeds 0x4DC maximum" );
 
-            byte[] buf = new byte[length];
-            ms.Read(buf, 0, buf.Length);
+            byte[] buf = new byte[ length ];
+            ms.Read( buf, 0, buf.Length );
 
-            Payload = new MemoryStream(buf);
-            Header.PayloadSize = (ushort) Payload.Length;
-            Header.MsgSize = (uint) Payload.Length;
+            var payload = new MemoryStream( buf );
+            header.PayloadSize = ( ushort )payload.Length;
+            header.MsgSize = ( uint )payload.Length;
+            return payload;
         }
 
         /// <summary>
diff --git a/SteamKit2/SteamKit2/Steam/Discovery/BasicServerListProto.cs b/SteamKit2/SteamKit2/Steam/Discovery/BasicServerListProto.cs
index e651cfe7b..c29b51fef 100644
--- a/SteamKit2/SteamKit2/Steam/Discovery/BasicServerListProto.cs
+++ b/SteamKit2/SteamKit2/Steam/Discovery/BasicServerListProto.cs
@@ -1,14 +1,12 @@
-using System.Diagnostics.CodeAnalysis;
-using ProtoBuf;
+using ProtoBuf;
 
 namespace SteamKit2.Discovery
 {
     [ProtoContract]
     class BasicServerListProto
     {
-        [ProtoMember(1)]
-        [DisallowNull, NotNull]
-        public string? Address { get; set; }
+        [ProtoMember( 1 )]
+        public string Address { get; set; } = string.Empty;
 
         [ProtoMember(2)]
         public int Port { get; set; }
diff --git a/SteamKit2/SteamKit2/Steam/Discovery/FileStorageServerListProvider.cs b/SteamKit2/SteamKit2/Steam/Discovery/FileStorageServerListProvider.cs
index 1da39e9a6..e46683191 100644
--- a/SteamKit2/SteamKit2/Steam/Discovery/FileStorageServerListProvider.cs
+++ b/SteamKit2/SteamKit2/Steam/Discovery/FileStorageServerListProvider.cs
@@ -35,10 +35,7 @@ public Task<IEnumerable<ServerRecord>> FetchServerListAsync()
                     using (FileStream fileStream = File.OpenRead(filename))
                     {
                         return Serializer.DeserializeItems<BasicServerListProto>(fileStream, PrefixStyle.Base128, 1)
-                            .Select(item =>
-                            {
-                                return ServerRecord.CreateServer(item.Address, item.Port, item.Protocols);
-                            })
+                            .Select(item => ServerRecord.CreateServer(item.Address, item.Port, item.Protocols))
                             .ToList();
                     }
                 }
diff --git a/SteamKit2/SteamKit2/Steam/Discovery/IsolatedStorageServerListProvider.cs b/SteamKit2/SteamKit2/Steam/Discovery/IsolatedStorageServerListProvider.cs
index 089ef31eb..fc7a53342 100644
--- a/SteamKit2/SteamKit2/Steam/Discovery/IsolatedStorageServerListProvider.cs
+++ b/SteamKit2/SteamKit2/Steam/Discovery/IsolatedStorageServerListProvider.cs
@@ -38,10 +38,7 @@ public Task<IEnumerable<ServerRecord>> FetchServerListAsync()
                     using (var fileStream = isolatedStorage.OpenFile(FileName, FileMode.OpenOrCreate, FileAccess.ReadWrite))
                     {
                         return Serializer.DeserializeItems<BasicServerListProto>(fileStream, PrefixStyle.Base128, 1)
-                            .Select(item =>
-                            {
-                                return ServerRecord.CreateServer(item.Address, item.Port, item.Protocols);
-                            })
+                            .Select(item => ServerRecord.CreateServer(item.Address, item.Port, item.Protocols))
                             .ToList();
                     }
                 }
diff --git a/SteamKit2/SteamKit2/Steam/Handlers/SteamUnifiedMessages/Callbacks.cs b/SteamKit2/SteamKit2/Steam/Handlers/SteamUnifiedMessages/Callbacks.cs
index b7d46d398..206aa57b5 100644
--- a/SteamKit2/SteamKit2/Steam/Handlers/SteamUnifiedMessages/Callbacks.cs
+++ b/SteamKit2/SteamKit2/Steam/Handlers/SteamUnifiedMessages/Callbacks.cs
@@ -3,13 +3,11 @@
  * file 'license.txt', which is part of this source code package.
  */
 
-using ProtoBuf;
-using System.IO;
-using System.Linq;
-using SteamKit2.Internal;
 using System;
+using System.IO;
 using System.Reflection;
-using System.Diagnostics.CodeAnalysis;
+using ProtoBuf;
+using SteamKit2.Internal;
 
 namespace SteamKit2
 {
@@ -101,30 +99,26 @@ public string RpcName
             /// <summary>
             /// Gets the full name of the service method.
             /// </summary>
-            [DisallowNull, NotNull]
-            public string? MethodName { get; private set; }
+            public string MethodName { get; private set; }
 
             /// <summary>
             /// Gets the protobuf notification body.
             /// </summary>
-            [DisallowNull, NotNull]
-            public object? Body { get; private set; }
+            public object Body { get; private set; }
 
 
             internal ServiceMethodNotification( Type messageType, IPacketMsg packetMsg )
             {
                 // Bounce into generic-land.
-                var setupMethod = GetType().GetMethod( nameof(Setup), BindingFlags.Instance | BindingFlags.NonPublic ).MakeGenericMethod( messageType );
-                setupMethod.Invoke( this, new[] { packetMsg } );
+                var setupMethod = GetType().GetMethod( nameof(Setup), BindingFlags.Static | BindingFlags.NonPublic ).MakeGenericMethod( messageType );
+                (MethodName, Body) = ((string, object))setupMethod.Invoke( this, new[] { packetMsg } );
             }
 
-            void Setup<T>( IPacketMsg packetMsg )
+            static (string methodName, object body) Setup<T>( IPacketMsg packetMsg )
                 where T : IExtensible, new()
             {
                 var clientMsg = new ClientMsgProtobuf<T>( packetMsg );
-
-                MethodName = clientMsg.Header.Proto.target_job_name;
-                Body = clientMsg.Body;
+                return (clientMsg.Header.Proto.target_job_name, clientMsg.Body);
             }
         }
     }