METADAPT-A writing is goroutine safe

metadapta.go

@@ -233,7 +233,7 @@ type transA struct {
 	closeErr      error
 	
 	currentReader  io.Reader
-	currentWriter io.Closer
+	currentWriter  usync.Monitor[io.Closer]
 	
 	deadline      *time.Timer
 	deadlineLock  sync.Mutex
@@ -270,10 +270,13 @@ func (this *transA) Send(method uint16, data []byte) error {
 }
 
 func (this *transA) SendWriter(method uint16) (io.WriteCloser, error) {
+	currentWriter, done := this.currentWriter.BorrowReturn()
+	defer done(&currentWriter)
+
 	// close previous writer if necessary
-	if this.currentWriter != nil {
-		this.currentWriter.Close()
-		this.currentWriter = nil
+	if currentWriter != nil {
+		currentWriter.Close()
+		currentWriter = nil
 	}
 
 	// create new writer
@@ -284,7 +287,7 @@ func (this *transA) SendWriter(method uint16) (io.WriteCloser, error) {
 		chunkSize: defaultChunkSize,
 		open: true,
 	}
-	this.currentWriter = writer
+	currentWriter = writer
 	return writer, nil
 }