Added AudioOutStream, exposed Clear/ClearAsync methods. Added support for cancelTokens.

src/Discord.Net.Core/Audio/AudioOutStream.cs

@@ -0,0 +1,16 @@
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Discord.Audio
+{
+    public abstract class AudioOutStream : Stream
+    {
+        public override bool CanRead => false;
+        public override bool CanSeek => false;
+        public override bool CanWrite => true;
+
+        public virtual void Clear() { }
+        public virtual Task ClearAsync(CancellationToken cancelToken) { return Task.Delay(0); }
+    }
+}

src/Discord.Net.Core/Audio/IAudioClient.cs

@@ -22,26 +22,26 @@ namespace Discord.Audio
         /// </summary>
         /// <param name="samplesPerFrame">Samples per frame. Must be 120, 240, 480, 960, 1920 or 2880, representing 2.5, 5, 10, 20, 40 or 60 milliseconds respectively.</param>
         /// <returns></returns>
-        Stream CreateOpusStream(int samplesPerFrame, int bufferMillis = 1000);
+        AudioOutStream CreateOpusStream(int samplesPerFrame, int bufferMillis = 1000);
         /// <summary>
         /// Creates a new outgoing stream accepting Opus-encoded data. This is a direct stream with no internal timer.
         /// </summary>
         /// <param name="samplesPerFrame">Samples per frame. Must be 120, 240, 480, 960, 1920 or 2880, representing 2.5, 5, 10, 20, 40 or 60 milliseconds respectively.</param>
         /// <returns></returns>
-        Stream CreateDirectOpusStream(int samplesPerFrame);
+        AudioOutStream CreateDirectOpusStream(int samplesPerFrame);
         /// <summary>
         /// Creates a new outgoing stream accepting PCM (raw) data.
         /// </summary>
         /// <param name="samplesPerFrame">Samples per frame. Must be 120, 240, 480, 960, 1920 or 2880, representing 2.5, 5, 10, 20, 40 or 60 milliseconds respectively.</param>
         /// <param name="bitrate"></param>
         /// <returns></returns>
-        Stream CreatePCMStream(int samplesPerFrame, int channels = 2, int? bitrate = null, int bufferMillis = 1000);
+        AudioOutStream CreatePCMStream(int samplesPerFrame, int channels = 2, int? bitrate = null, int bufferMillis = 1000);
         /// <summary>
         /// Creates a new direct outgoing stream accepting PCM (raw) data. This is a direct stream with no internal timer.
         /// </summary>
         /// <param name="samplesPerFrame">Samples per frame. Must be 120, 240, 480, 960, 1920 or 2880, representing 2.5, 5, 10, 20, 40 or 60 milliseconds respectively.</param>
         /// <param name="bitrate"></param>
         /// <returns></returns>
-        Stream CreateDirectPCMStream(int samplesPerFrame, int channels = 2, int? bitrate = null);
+        AudioOutStream CreateDirectPCMStream(int samplesPerFrame, int channels = 2, int? bitrate = null);
     }
 }

src/Discord.Net.WebSocket/Audio/AudioClient.cs

@@ -170,25 +170,25 @@ namespace Discord.Audio
             await Discord.ApiClient.SendVoiceStateUpdateAsync(Guild.Id, null, false, false).ConfigureAwait(false);
         }
 
-        public Stream CreateOpusStream(int samplesPerFrame, int bufferMillis)
+        public AudioOutStream CreateOpusStream(int samplesPerFrame, int bufferMillis)
         {
             CheckSamplesPerFrame(samplesPerFrame);
             var target = new BufferedAudioTarget(ApiClient, samplesPerFrame, bufferMillis, _cancelTokenSource.Token);
             return new RTPWriteStream(target, _secretKey, samplesPerFrame, _ssrc);
         }
-        public Stream CreateDirectOpusStream(int samplesPerFrame)
+        public AudioOutStream CreateDirectOpusStream(int samplesPerFrame)
         {
             CheckSamplesPerFrame(samplesPerFrame);
             var target = new DirectAudioTarget(ApiClient);
             return new RTPWriteStream(target, _secretKey, samplesPerFrame, _ssrc);
         }
-        public Stream CreatePCMStream(int samplesPerFrame, int channels, int? bitrate, int bufferMillis)
+        public AudioOutStream CreatePCMStream(int samplesPerFrame, int channels, int? bitrate, int bufferMillis)
         {
             CheckSamplesPerFrame(samplesPerFrame);
             var target = new BufferedAudioTarget(ApiClient, samplesPerFrame, bufferMillis, _cancelTokenSource.Token);
             return new OpusEncodeStream(target, _secretKey, channels, samplesPerFrame, _ssrc, bitrate);
         }
-        public Stream CreateDirectPCMStream(int samplesPerFrame, int channels, int? bitrate)
+        public AudioOutStream CreateDirectPCMStream(int samplesPerFrame, int channels, int? bitrate)
         {
             CheckSamplesPerFrame(samplesPerFrame);
             var target = new DirectAudioTarget(ApiClient);

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

@@ -5,7 +5,7 @@ using System.Threading.Tasks;
 
 namespace Discord.Audio
 {
-    internal class RTPWriteStream : Stream
+    internal class RTPWriteStream : AudioOutStream
     {
         private readonly IAudioTarget _target;
         private readonly byte[] _nonce, _secretKey;
@@ -14,10 +14,6 @@ namespace Discord.Audio
 
         protected readonly byte[] _buffer;
 
-        public override bool CanRead => false;
-        public override bool CanSeek => false;
-        public override bool CanWrite => true;
-
         internal RTPWriteStream(IAudioTarget target, byte[] secretKey, int samplesPerFrame, uint ssrc)
         {
             _target = target;
@@ -40,6 +36,7 @@ namespace Discord.Audio
         }
         public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
         {
+            cancellationToken.ThrowIfCancellationRequested();
             unchecked
             {
                 if (_nonce[3]++ == byte.MaxValue)
@@ -63,7 +60,16 @@ namespace Discord.Audio
         }
         public override async Task FlushAsync(CancellationToken cancellationToken)
         {
-            await _target.FlushAsync().ConfigureAwait(false);
+            await _target.FlushAsync(cancellationToken).ConfigureAwait(false);
+        }
+
+        public override void Clear()
+        {
+            ClearAsync(CancellationToken.None).GetAwaiter().GetResult();
+        }
+        public override async Task ClearAsync(CancellationToken cancelToken)
+        {
+            await _target.ClearAsync(cancelToken).ConfigureAwait(false);
         }
 
         public override long Length { get { throw new NotSupportedException(); } }

src/Discord.Net.WebSocket/Audio/Targets/BufferedAudioTarget.cs

@@ -87,17 +87,25 @@ namespace Discord.Audio
             Buffer.BlockCopy(data, 0, buffer, 0, count);
             _queuedFrames.Enqueue(new Frame(buffer, count));
         }
-
-        public async Task FlushAsync()
+        
+        public async Task FlushAsync(CancellationToken cancelToken)
         {
             while (true)
             {
+                cancelToken.ThrowIfCancellationRequested();
                 if (_queuedFrames.Count == 0)
                     return;
-                await Task.Delay(250).ConfigureAwait(false);
+                await Task.Delay(250, cancelToken).ConfigureAwait(false);
             }
         }
-
+        public Task ClearAsync(CancellationToken cancelToken)
+        {
+            Frame ignored;
+            do
+                cancelToken.ThrowIfCancellationRequested();
+            while (_queuedFrames.TryDequeue(out ignored));
+            return Task.Delay(0);
+        }
         protected void Dispose(bool disposing)
         {
             if (disposing)

src/Discord.Net.WebSocket/Audio/Targets/DirectAudioTarget.cs

@@ -1,4 +1,5 @@
-using System.Threading.Tasks;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace Discord.Audio
 {
@@ -13,7 +14,9 @@ namespace Discord.Audio
         public Task SendAsync(byte[] buffer, int count)
             => _client.SendAsync(buffer, count);
 
-        public Task FlushAsync()
+        public Task FlushAsync(CancellationToken cancelToken)
+            => Task.Delay(0);
+        public Task ClearAsync(CancellationToken cancelToken)
             => Task.Delay(0);
     }
 }

src/Discord.Net.WebSocket/Audio/Targets/IAudioTarget.cs

@@ -1,10 +1,12 @@
-using System.Threading.Tasks;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace Discord.Audio
 {
     internal interface IAudioTarget
     {
         Task SendAsync(byte[] buffer, int count);
-        Task FlushAsync();
+        Task FlushAsync(CancellationToken cancelToken);
+        Task ClearAsync(CancellationToken cancelToken);
     }
 }