diff --git a/Cargo.toml b/Cargo.toml
index cbdd95b0..391c3e3f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ license = "MIT"
 [dependencies]
 bytes = "0.4"
 futures = "0.1"
+nohash-hasher = { git = "https://github.com/paritytech/nohash-hasher" }
 log = "0.4"
 parking_lot = "0.6"
 quick-error = "0.1"
diff --git a/src/lib.rs b/src/lib.rs
index 2fa44bd1..2daf7c0e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -20,6 +20,7 @@
 extern crate bytes;
 #[macro_use]
 extern crate futures;
+extern crate nohash_hasher;
 #[macro_use]
 extern crate log;
 extern crate parking_lot;
diff --git a/src/notify/mod.rs b/src/notify.rs
similarity index 78%
rename from src/notify/mod.rs
rename to src/notify.rs
index 80b90383..bde11085 100644
--- a/src/notify/mod.rs
+++ b/src/notify.rs
@@ -17,11 +17,10 @@
 // WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 // CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-mod hash;
 
 use futures::{executor, task};
 use parking_lot::Mutex;
-use self::hash::HashMap;
+use nohash_hasher::IntMap;
 use std::sync::atomic::{AtomicUsize, Ordering};
 
 
@@ -32,19 +31,27 @@ task_local!{
 }
 
 
+/// A notifier maintains a collection of tasks which should be
+/// notified at some point. Useful in conjuction with `futures::executor::Spawn`.
 pub struct Notifier {
-    tasks: Mutex<HashMap<usize, task::Task>>
+    tasks: Mutex<IntMap<usize, task::Task>>
 }
 
 impl Notifier {
     pub fn new() -> Self {
-        Notifier { tasks: Mutex::new(HashMap::default()) }
+        Notifier { tasks: Mutex::new(IntMap::default()) }
     }
 
+    /// Insert the current task to the set of tasks to be notified.
+    ///
+    /// # Panics
+    ///
+    /// If called outside of a tokio task.
     pub fn insert_current(&self) {
         self.tasks.lock().insert(TASK_ID.with(|&t| t), task::current());
     }
 
+    /// Notify all registered tasks.
     pub fn notify_all(&self) {
         let mut tasks = self.tasks.lock();
         for (_, t) in tasks.drain() {
@@ -52,6 +59,7 @@ impl Notifier {
         }
     }
 
+    /// Return the number of currently registered tasks.
     pub fn len(&self) -> usize {
         self.tasks.lock().len()
     }
diff --git a/src/notify/hash.rs b/src/notify/hash.rs
deleted file mode 100644
index 07681132..00000000
--- a/src/notify/hash.rs
+++ /dev/null
@@ -1,44 +0,0 @@
-// Copyright 2018 Parity Technologies (UK) Ltd.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy of
-// this software and associated documentation files (the "Software"), to deal in
-// the Software without restriction, including without limitation the rights to
-// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
-// the Software, and to permit persons to whom the Software is furnished to do so,
-// subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all
-// copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
-// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
-// OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
-// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
-// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-use std::{self, hash::{BuildHasherDefault, Hasher}, marker::PhantomData};
-
-pub type HashMap<K, V> =
-    std::collections::HashMap<K, V, BuildHasherDefault<Stateless<K>>>;
-
-#[derive(Copy, Clone, Debug, Default)]
-pub struct Stateless<T>(u64, PhantomData<T>);
-
-impl Hasher for Stateless<usize> {
-    fn finish(&self) -> u64 { self.0 }
-    fn write(&mut self, _: &[u8]) { unimplemented!() }
-    fn write_u8(&mut self, _: u8) {unimplemented!() }
-    fn write_u16(&mut self, _: u16) { unimplemented!() }
-    fn write_u32(&mut self, _: u32) { unimplemented!() }
-    fn write_u64(&mut self, _: u64) { unimplemented!() }
-    fn write_u128(&mut self, _: u128) { unimplemented!() }
-    fn write_usize(&mut self, n: usize) { self.0 = n as u64 }
-    fn write_i8(&mut self, _: i8) { unimplemented!() }
-    fn write_i16(&mut self, _: i16) { unimplemented!() }
-    fn write_i32(&mut self, _: i32) { unimplemented!() }
-    fn write_i64(&mut self, _: i64) { unimplemented!() }
-    fn write_i128(&mut self, _: i128) { unimplemented!() }
-    fn write_isize(&mut self, _: isize) { unimplemented!() }
-}
-