feature: Implement Dispose for types which have disposable data (#1171)

* Initial set of dispose implementations

Not handled yet:
- Discord.Net.Websocket/Entities/SocketGuild
- Discord.Net.Tests

* Refactor DiscordSocketClient init into ctor

This way we remove an IDisposableAnalyzer warning for not disposing
the client when we set the client variable.

* Dispose of clients when disposing sharded client

* Finish implementing IDisposable where appropriate

I opted to use NoWarn in the Tests project as it wasn't really necessary
considering that our tests only run once

* Tweak samples after feedback

src/Discord.Net.WebSocket/Audio/Streams/BufferedWriteStream.cs

@@ -27,7 +27,7 @@ namespace Discord.Audio.Streams
 
         private readonly AudioClient _client;
         private readonly AudioStream _next;
-        private readonly CancellationTokenSource _cancelTokenSource;
+        private readonly CancellationTokenSource _disposeTokenSource, _cancelTokenSource;
         private readonly CancellationToken _cancelToken;
         private readonly Task _task;
         private readonly ConcurrentQueue<Frame> _queuedFrames;
@@ -49,12 +49,13 @@ namespace Discord.Audio.Streams
             _logger = logger;
             _queueLength = (bufferMillis + (_ticksPerFrame - 1)) / _ticksPerFrame; //Round up
 
-            _cancelTokenSource = new CancellationTokenSource();
-            _cancelToken = CancellationTokenSource.CreateLinkedTokenSource(_cancelTokenSource.Token, cancelToken).Token;
+            _disposeTokenSource = new CancellationTokenSource();
+            _cancelTokenSource = CancellationTokenSource.CreateLinkedTokenSource(_disposeTokenSource.Token, cancelToken);
+            _cancelToken = _cancelTokenSource.Token;
             _queuedFrames = new ConcurrentQueue<Frame>();
             _bufferPool = new ConcurrentQueue<byte[]>();
             for (int i = 0; i < _queueLength; i++)
-                _bufferPool.Enqueue(new byte[maxFrameSize]); 
+                _bufferPool.Enqueue(new byte[maxFrameSize]);
             _queueLock = new SemaphoreSlim(_queueLength, _queueLength);
             _silenceFrames = MaxSilenceFrames;
 
@@ -63,7 +64,12 @@ namespace Discord.Audio.Streams
         protected override void Dispose(bool disposing)
         {
             if (disposing)
-                _cancelTokenSource.Cancel();
+            {
+                _disposeTokenSource?.Cancel();
+                _disposeTokenSource?.Dispose();
+                _cancelTokenSource?.Dispose();
+                _queueLock?.Dispose();
+            }
             base.Dispose(disposing);
         }
 
@@ -131,8 +137,12 @@ namespace Discord.Audio.Streams
         public override void WriteHeader(ushort seq, uint timestamp, bool missed) { } //Ignore, we use our own timing
         public override async Task WriteAsync(byte[] data, int offset, int count, CancellationToken cancelToken)
         {
+            CancellationTokenSource writeCancelToken = null;
             if (cancelToken.CanBeCanceled)
-                cancelToken = CancellationTokenSource.CreateLinkedTokenSource(cancelToken, _cancelToken).Token;
+            {
+                writeCancelToken = CancellationTokenSource.CreateLinkedTokenSource(cancelToken, _cancelToken);
+                cancelToken = writeCancelToken.Token;
+            }
             else
                 cancelToken = _cancelToken;
 
@@ -142,6 +152,9 @@ namespace Discord.Audio.Streams
 #if DEBUG
                 var _ = _logger?.DebugAsync("Buffer overflow"); //Should never happen because of the queueLock
 #endif
+#pragma warning disable IDISP016
+                writeCancelToken?.Dispose();
+#pragma warning restore IDISP016
                 return;
             }
             Buffer.BlockCopy(data, offset, buffer, 0, count);
@@ -153,6 +166,7 @@ namespace Discord.Audio.Streams
 #endif
                 _isPreloaded = true;
             }
+            writeCancelToken?.Dispose();
         }
 
         public override async Task FlushAsync(CancellationToken cancelToken)

src/Discord.Net.WebSocket/Audio/Streams/InputStream.cs

@@ -96,7 +96,17 @@ namespace Discord.Audio.Streams
 
         protected override void Dispose(bool isDisposing)
         {
-            _isDisposed = true;
+            if (!_isDisposed)
+            {
+                if (isDisposing)
+                {
+                    _signal?.Dispose();
+                }
+
+                _isDisposed = true;
+            }
+
+            base.Dispose(isDisposing);
         }
     }
 }