More audio cleanup, finished receive streams

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

@@ -0,0 +1,73 @@
+using System;
+using System.Collections.Concurrent;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Discord.Audio.Streams
+{
+    ///<summary> Reads the payload from an RTP frame </summary>
+    public class InputStream : AudioInStream
+    {
+        private ConcurrentQueue<RTPFrame> _frames;
+        private ushort _nextSeq;
+        private uint _nextTimestamp;
+        private bool _hasHeader;
+
+        public override bool CanRead => true;
+        public override bool CanSeek => false;
+        public override bool CanWrite => true;
+
+        public InputStream(byte[] secretKey)
+        {
+            _frames = new ConcurrentQueue<RTPFrame>();
+        }
+
+        public override Task<RTPFrame?> ReadFrameAsync(CancellationToken cancelToken)
+        {
+            if (_frames.TryDequeue(out var frame))
+                return Task.FromResult<RTPFrame?>(frame);
+            return Task.FromResult<RTPFrame?>(null);
+        }
+        public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancelToken)
+        {
+            cancelToken.ThrowIfCancellationRequested();
+            
+            if (_frames.TryDequeue(out var frame))
+            {
+                if (count < frame.Payload.Length)
+                    throw new InvalidOperationException("Buffer is too small.");
+                Buffer.BlockCopy(frame.Payload, 0, buffer, offset, frame.Payload.Length);
+                return Task.FromResult(frame.Payload.Length);
+            }
+            return Task.FromResult(0);
+        }
+
+        public void WriteHeader(ushort seq, uint timestamp)
+        {
+            if (_hasHeader)
+                throw new InvalidOperationException("Header received with no payload");
+            _hasHeader = true;
+            _nextSeq = seq;
+            _nextTimestamp = timestamp;
+        }
+        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancelToken)
+        {
+            cancelToken.ThrowIfCancellationRequested();
+
+            if (_frames.Count > 1000)
+                return Task.Delay(0); //Buffer overloaded
+            if (_hasHeader)
+                throw new InvalidOperationException("Received payload with an RTP header");
+            byte[] payload = new byte[count];
+            Buffer.BlockCopy(buffer, offset, payload, 0, count);
+
+            _frames.Enqueue(new RTPFrame(
+                sequence: _nextSeq,
+                timestamp: _nextTimestamp,
+                payload: payload
+            ));
+            _hasHeader = false;
+            return Task.Delay(0);
+        }
+    }
+}