diff --git a/internal/framing/frame.go b/internal/framing/frame.go
index f998127..797cdfc 100644
--- a/internal/framing/frame.go
+++ b/internal/framing/frame.go
@@ -143,7 +143,7 @@ type Frame interface {
 	// IsResumable returns true if frame supports resume.
 	IsResumable() bool
 	// Done marks current frame has been sent.
-	Done()
+	Done() (closed bool)
 	// DoneNotify notifies when frame done.
 	DoneNotify() <-chan struct{}
 }
@@ -156,8 +156,14 @@ type BaseFrame struct {
 }
 
 // Done can be invoked when a frame has been been processed.
-func (p *BaseFrame) Done() {
+func (p *BaseFrame) Done() (closed bool) {
+	defer func() {
+		if e := recover(); e != nil {
+			closed = true
+		}
+	}()
 	close(p.done)
+	return
 }
 
 // DoneNotify notify when frame has been done.
diff --git a/internal/socket/duplex.go b/internal/socket/duplex.go
index 8e5d3c2..45c6eae 100644
--- a/internal/socket/duplex.go
+++ b/internal/socket/duplex.go
@@ -984,10 +984,9 @@ func (p *DuplexRSocket) drainOutBack() {
 	var out framing.Frame
 	for i := range p.outsPriority {
 		out = p.outsPriority[i]
-		if p.tp != nil {
-			if err := p.tp.Send(out, false); err != nil {
-				logger.Errorf("send frame failed: %v\n", err)
-			}
+		if err := p.tp.Send(out, false); err != nil {
+			out.Done()
+			logger.Errorf("send frame failed: %v\n", err)
 		}
 	}
 	if err := p.tp.Flush(); err != nil {
diff --git a/internal/transport/transport.go b/internal/transport/transport.go
index 113d2d2..c89f064 100644
--- a/internal/transport/transport.go
+++ b/internal/transport/transport.go
@@ -19,6 +19,8 @@ type (
 	ServerTransportAcceptor = func(ctx context.Context, tp *Transport)
 )
 
+var errTransportClosed = errors.New("transport closed")
+
 // ServerTransport is server-side RSocket transport.
 type ServerTransport interface {
 	io.Closer
@@ -76,26 +78,36 @@ func (p *Transport) SetLifetime(lifetime time.Duration) {
 }
 
 // Send send a frame.
-func (p *Transport) Send(frame framing.Frame, flush bool) error {
-	defer frame.Done()
-	if err := p.conn.Write(frame); err != nil {
-		return errors.Wrap(err, "send failed")
+func (p *Transport) Send(frame framing.Frame, flush bool) (err error) {
+	defer func() {
+		// ensure frame done when send success.
+		if err == nil {
+			frame.Done()
+		}
+	}()
+	if p == nil || p.conn == nil {
+		err = errTransportClosed
+		return
 	}
-	if !flush {
-		return nil
+	err = p.conn.Write(frame)
+	if err != nil {
+		return
 	}
-	if err := p.conn.Flush(); err != nil {
-		return errors.Wrap(err, "flush failed")
+	if !flush {
+		return
 	}
-	return nil
+	err = p.conn.Flush()
+	return
 }
 
 // Flush flush all bytes in current connection.
-func (p *Transport) Flush() error {
-	if err := p.conn.Flush(); err != nil {
-		return errors.Wrap(err, "flush failed")
+func (p *Transport) Flush() (err error) {
+	if p == nil || p.conn == nil {
+		err = errTransportClosed
+		return
 	}
-	return nil
+	err = p.conn.Flush()
+	return
 }
 
 // Close close current transport.
diff --git a/rx/rx.go b/rx/rx.go
index cc428b6..6ed6c57 100644
--- a/rx/rx.go
+++ b/rx/rx.go
@@ -26,7 +26,7 @@ type (
 	FnOnNext = func(input payload.Payload)
 	// FnOnSubscribe is alias of function for signal when subscribe begin.
 	FnOnSubscribe = func(s Subscription)
-	// FnOnError is alias of function for signal when an error occured.
+	// FnOnError is alias of function for signal when an error occurred.
 	FnOnError = func(e error)
 	// FnOnCancel is alias of function for signal when subscription canceled.
 	FnOnCancel = func()