[Modify] Polish it

websocket-sharp/Net/Chunk.cs

@@ -74,13 +74,15 @@ namespace WebSocketSharp.Net
     public int Read (byte[] buffer, int offset, int count)
     {
       var left = _data.Length - _offset;
+
       if (left == 0)
-        return left;
+        return 0;
 
       if (count > left)
         count = left;
 
       Buffer.BlockCopy (_data, _offset, buffer, offset, count);
+
       _offset += count;
 
       return count;