Added Pool utility class

src/Discord.Net.Core/Discord.Net.Core.csproj

@@ -7,11 +7,11 @@
     <TargetFrameworks>net45;netstandard1.1;netstandard1.3</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="System.Buffers" Version="4.4.0-preview2-25405-01" />
-    <PackageReference Include="System.Collections.Immutable" Version="1.3.1" />
+    <PackageReference Include="System.Buffers" Version="4.4.0" />
+    <PackageReference Include="System.Collections.Immutable" Version="1.4.0" />
     <PackageReference Include="System.Interactive.Async" Version="3.1.1" />
     <PackageReference Include="System.Memory" Version="4.4.0-preview2-25405-01" />
-    <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="4.4.0-preview2-25405-01" />
+    <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="4.4.0" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Discord.Net.Serialization\Discord.Net.Serialization.csproj" />

src/Discord.Net.Rest/DiscordRestApiClient.cs

@@ -4,8 +4,6 @@ using Discord.Net;
 using Discord.Net.Queue;
 using Discord.Net.Rest;
 using Discord.Serialization;
-using Discord.Serialization.Json;
-using Discord.Serialization.Json.Converters;
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
@@ -13,7 +11,6 @@ using System.Diagnostics;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Net;
-using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Text;
 using System.Text.Formatting;
@@ -31,7 +28,7 @@ namespace Discord.API
         
         protected readonly SemaphoreSlim _stateLock;
         protected readonly Serializer _serializer;
-        protected readonly ConcurrentQueue<ArrayFormatter> _formatters;
+        protected readonly Pool<ArrayFormatter> _formatters;
         private readonly RestClientProvider _restClientProvider;
 
         protected bool _isDisposed;
@@ -56,7 +53,7 @@ namespace Discord.API
 
             RequestQueue = new RequestQueue();
             _stateLock = new SemaphoreSlim(1, 1);
-            _formatters = new ConcurrentQueue<ArrayFormatter>();
+            _formatters = new Pool<ArrayFormatter>(() => new ArrayFormatter(128, SymbolTable.InvariantUtf8));
 
             SetBaseUrl(DiscordConfig.APIUrl);
         }
@@ -190,9 +187,8 @@ namespace Discord.API
             options.HeaderOnly = true;
             options.BucketId = AuthTokenType == TokenType.User ? ClientBucket.Get(clientBucket).Id : bucketId;
             options.IsClientBucket = AuthTokenType == TokenType.User;
-
-            if (!_formatters.TryDequeue(out var data))
-                data = new ArrayFormatter(128, SymbolTable.InvariantUtf8);
+            
+            var data = _formatters.Rent();
             try
             {
                 var request = new JsonRestRequest(RestClient, method, endpoint, SerializeJson(data, payload), options);
@@ -201,7 +197,7 @@ namespace Discord.API
             finally
             {
                 data.Clear();
-                _formatters.Enqueue(data);
+                _formatters.Return(data);
             }
         }
 
@@ -244,8 +240,7 @@ namespace Discord.API
             options.BucketId = AuthTokenType == TokenType.User ? ClientBucket.Get(clientBucket).Id : bucketId;
             options.IsClientBucket = AuthTokenType == TokenType.User;
 
-            if (!_formatters.TryDequeue(out var data))
-                data = new ArrayFormatter(128, SymbolTable.InvariantUtf8);
+            var data = _formatters.Rent();
             try
             {
                 var request = new JsonRestRequest(RestClient, method, endpoint, SerializeJson(data, payload), options);
@@ -254,7 +249,7 @@ namespace Discord.API
             finally
             {
                 data.Clear();
-                _formatters.Enqueue(data);
+                _formatters.Return(data);
             }
         }
 

src/Discord.Net.Rpc/DiscordRpcApiClient.cs

@@ -225,8 +225,7 @@ namespace Discord.API
         private async Task<TResponse> SendRpcAsyncInternal<TResponse>(string cmd, object payload, Optional<string> evt, RequestOptions options)
             where TResponse : class, new()
         {
-            if (_formatters.TryDequeue(out var data))
-                data = new ArrayFormatter(128, SymbolTable.InvariantUtf8);
+            var data = _formatters.Rent();
             try
             {
                 var guid = Guid.NewGuid();
@@ -241,7 +240,8 @@ namespace Discord.API
             }
             finally
             {
-                _formatters.Enqueue(data);
+                data.Clear();
+                _formatters.Return(data);
             }
         }
 

src/Discord.Net.Serialization/Utils/Pool.cs

@@ -0,0 +1,71 @@
+using System;
+using System.Diagnostics;
+using System.Threading;
+
+namespace Discord.Serialization
+{
+    //TODO: Replace pools in audio with this
+    public sealed class Pool<T>
+        where T : class
+    {
+        private const int DefaultMaxElementsPerBucket = 50;
+
+        private readonly T[] _buffer;
+        private readonly Func<T> _createFunc;
+
+        private SpinLock _lock;
+        private int _index;
+
+        public Pool(Func<T> createFunc)
+            : this(createFunc, DefaultMaxElementsPerBucket) { }
+        public Pool(Func<T> createFunc, int maxElementsPerBucket)
+        {
+            _createFunc = createFunc;
+            _lock = new SpinLock(Debugger.IsAttached);
+            _buffer = new T[maxElementsPerBucket];
+        }
+
+        public T Rent()
+        {
+            T result = null;
+            bool lockTaken = false;
+            try
+            {
+                _lock.Enter(ref lockTaken);
+
+                if (_index < _buffer.Length)
+                {
+                    result = _buffer[_index];
+                    _buffer[_index++] = null;
+                }
+            }
+            finally
+            {
+                if (lockTaken)
+                    _lock.Exit(false);
+            }
+            
+            if (result == null)
+                result = _createFunc();
+
+            return result;
+        }
+
+        public void Return(T obj)
+        {
+            bool lockTaken = false;
+            try
+            {
+                _lock.Enter(ref lockTaken);
+
+                if (_index != 0)
+                    _buffer[--_index] = obj;
+            }
+            finally
+            {
+                if (lockTaken)
+                    _lock.Exit(false);
+            }
+        }
+    }
+}

src/Discord.Net.WebSocket/DiscordSocketApiClient.cs

@@ -174,8 +174,7 @@ namespace Discord.API
         {
             CheckState();
 
-            if (!_formatters.TryDequeue(out var data))
-                data = new ArrayFormatter(128, SymbolTable.InvariantUtf8);
+            var data = _formatters.Rent();
             try
             {
                 var frame = new GatewaySocketFrame { Operation = opCode, Payload = payload };
@@ -185,7 +184,7 @@ namespace Discord.API
             finally
             {
                 data.Clear();
-                _formatters.Enqueue(data);
+                _formatters.Return(data);
             }
         }
 

src/Discord.Net.WebSocket/DiscordVoiceApiClient.cs

@@ -41,7 +41,7 @@ namespace Discord.Audio
         private readonly Serializer _serializer;
         private readonly SemaphoreSlim _connectionLock;
         private readonly MemoryStream _decompressionStream;
-        protected readonly ConcurrentQueue<ArrayFormatter> _formatters;
+        protected readonly Pool<ArrayFormatter> _formatters;
 
         private CancellationTokenSource _connectCancelToken;
         private IUdpSocket _udp;
@@ -61,7 +61,7 @@ namespace Discord.Audio
             _udp = udpSocketProvider();
             _udp.ReceivedDatagram += (data, index, count) => _receivedPacketEvent.InvokeAsync(data, index, count);
             _serializer = serializer;
-            _formatters = new ConcurrentQueue<ArrayFormatter>();
+            _formatters = new Pool<ArrayFormatter>(() => new ArrayFormatter(128, SymbolTable.InvariantUtf8));
 
             _decompressionStream = new MemoryStream(10 * 1024); //10 KB
 
@@ -114,8 +114,7 @@ namespace Discord.Audio
 
         public async Task SendAsync(VoiceOpCode opCode, object payload, RequestOptions options = null)
         {
-            if (!_formatters.TryDequeue(out var data))
-                data = new ArrayFormatter(128, SymbolTable.InvariantUtf8);
+            var data = _formatters.Rent();
             try
             {
                 var frame = new VoiceSocketFrame { Operation = opCode, Payload = payload };
@@ -125,7 +124,7 @@ namespace Discord.Audio
             finally
             {
                 data.Clear();
-                _formatters.Enqueue(data);
+                _formatters.Return(data);
             }
         }
         public async Task SendAsync(byte[] data, int offset, int bytes)