Delay socket close so to (re)send final ACK if needed.

Author: michau-krakow

lib/protocol/reader.js

@@ -157,7 +157,10 @@ Reader.prototype._notifyWindow = function (block){
 
 	if (this._lastReceived){
 		this._noMoreData = true;
-		return this._close ();
+		this._readerTimer.reset ();
+		// RFC 1350 section 6: On the other hand, delaying is encouraged. This means that the host sending the final
+		// ACK will wait for a while before terminating in order to retransmit the final ACK if it has been lost
+		return setTimeout(() => this._close(), 5000);
 	}
 
 	this._pending = this._windowSize;
@@ -168,9 +171,11 @@ Reader.prototype._notifyWindow = function (block){
 };
 
 Reader.prototype._onData = function (message){
-	//DATA packet received after sending the last packet, the socket will be
-	//closed in the next tick
-	if (this._noMoreData) return;
+	//DATA packet received after sending the last packet, the socket is delay-closed so just ACK the client
+	if (this._noMoreData) {
+		this._sendAck(message.block);
+		return;
+	}
 
 	if (message.block === 0 && this._rolloverFix === 0){
 		//The server has rollovered to 0