Make write non-blocking for async transport.

src/Connection.cs

@@ -352,7 +352,7 @@ void Connect(SaslProfile saslProfile, Open open)
             if (WebSocketTransport.MatchScheme(address.Scheme))
             {
                 WebSocketTransport wsTransport = new WebSocketTransport();
-                wsTransport.ConnectAsync(address, null).GetAwaiter().GetResult();
+                wsTransport.ConnectAsync(address, null).ConfigureAwait(false).GetAwaiter().GetResult();
                 transport = wsTransport;
             }
             else

src/Net/TaskExtensions.cs

@@ -266,13 +266,24 @@ public static Task<Message> ReceiveAsync(this ReceiverLink receiver, int timeout
         internal static async Task<IAsyncTransport> OpenAsync(this SaslProfile saslProfile, string hostname,
             IBufferManager bufferManager, IAsyncTransport transport)
         {
-            ProtocolHeader header = saslProfile.Start(hostname, transport);
+            // if transport is closed, pump reader should throw exception
+            TransportWriter writer = new TransportWriter(transport, e => { });
+
+            ProtocolHeader myHeader = saslProfile.Start(hostname, writer);
 
             AsyncPump pump = new AsyncPump(bufferManager, transport);
 
             await pump.PumpAsync(
-                h => { saslProfile.OnHeader(header, h); return true; },
-                b => { SaslCode code; return saslProfile.OnFrame(transport, b, out code); });
+                header =>
+                {
+                    saslProfile.OnHeader(myHeader, header);
+                    return true;
+                },
+                buffer =>
+                {
+                    SaslCode code;
+                    return saslProfile.OnFrame(writer, buffer, out code);
+                });
 
             return (IAsyncTransport)saslProfile.UpgradeTransportInternal(transport);
         }

src/WinRT/TcpTransport.cs

@@ -83,12 +83,12 @@ public void Close()
 
         public void Send(ByteBuffer buffer)
         {
-            this.SendAsync(new ByteBuffer[] { buffer }, buffer.Length).GetAwaiter().GetResult();
+            this.SendAsync(new ByteBuffer[] { buffer }, buffer.Length).ConfigureAwait(false).GetAwaiter().GetResult();
         }
 
         public int Receive(byte[] buffer, int offset, int count)
         {
-            return this.ReceiveAsync(buffer, offset, count).GetAwaiter().GetResult();
+            return this.ReceiveAsync(buffer, offset, count).ConfigureAwait(false).GetAwaiter().GetResult();
         }
     }
 }

src/WinRT/WebSocketTransport.cs

@@ -109,12 +109,12 @@ void ITransport.Close()
 
         void ITransport.Send(ByteBuffer buffer)
         {
-            ((IAsyncTransport)this).SendAsync(new ByteBuffer[] { buffer }, buffer.Length).GetAwaiter().GetResult();
+            ((IAsyncTransport)this).SendAsync(new ByteBuffer[] { buffer }, buffer.Length).ConfigureAwait(false).GetAwaiter().GetResult();
         }
 
         int ITransport.Receive(byte[] buffer, int offset, int count)
         {
-            return ((IAsyncTransport)this).ReceiveAsync(buffer, offset, count).GetAwaiter().GetResult();
+            return ((IAsyncTransport)this).ReceiveAsync(buffer, offset, count).ConfigureAwait(false).GetAwaiter().GetResult();
         }
 
         static int GetDefaultPort(string scheme, int port)