Fix another "deadlock" in METADAPT-A

What fucking idiot go developer decided recv from a nil channel
locks the entire program. ?????? just have it return zero value and
false.

metadapta.go

@@ -104,7 +104,7 @@ func (this *a) receive() {
 		this.transLock.Lock()
 		defer this.transLock.Unlock()
 		for _, trans := range this.transMap {
-			trans.Close()
+			trans.closeDontUnlist()
 		}
 		clear(this.transMap)
 	}()
@@ -163,9 +163,13 @@ type transA struct {
 }
 
 func (this *transA) Close() error {
-	this.incoming.Close()
+	err := this.closeDontUnlist()
 	this.parent.unlistTransactionSafe(this.ID())
-	return nil
+	return err
+}
+
+func (this *transA) closeDontUnlist() error {
+	return this.incoming.Close()
 }
 
 func (this *transA) ID() int64 {
@@ -177,15 +181,18 @@ func (this *transA) Send(method uint16, data []byte) error {
 }
 
 func (this *transA) Receive() (method uint16, data []byte, err error) {
-	message, ok := <- this.incoming.Receive()
-	if !ok {
-		if this.parent.err == nil {
-			return 0, nil, fmt.Errorf("could not receive message: %w", io.EOF)
-		} else {
-			return 0, nil, this.parent.err
+	receive := this.incoming.Receive()
+	if receive != nil {
+		if message, ok := <- receive; ok {
+			return message.method, message.payload, nil
 		}
 	}
-	return message.method, message.payload, nil
+	
+	if this.parent.err == nil {
+		return 0, nil, fmt.Errorf("could not receive message: %w", io.EOF)
+	} else {
+		return 0, nil, this.parent.err
+	}
 }
 
 type incomingMessage struct {