refactor(writer): Optimizes the FrameWriter write logic and cleans up irrelevant comments.

Redundant comments have been removed from the `WriteFrame` and heartbeat control methods, and logic for releasing unprocessed frames in the queue has been added to the `Close` method to ensure proper resource reclamation. Some unnecessary channel signal comments have also been removed, making the code more concise and clear.

internal/shared/protocol/writer.go

@@ -128,15 +128,12 @@ func (w *FrameWriter) flushBatchLocked() {
 
 	for _, frame := range w.batch {
 		_ = WriteFrame(w.conn, frame)
-		// Release pooled buffer after writing
 		frame.Release()
 	}
 
 	w.batch = w.batch[:0]
 }
 
-// WriteFrame queues a frame to be written by the write loop.
-// Blocks if the queue is full to ensure all writes go through the single write loop.
 func (w *FrameWriter) WriteFrame(frame *Frame) error {
 	w.mu.Lock()
 	if w.closed {
@@ -163,6 +160,11 @@ func (w *FrameWriter) Close() error {
 	w.mu.Unlock()
 
 	close(w.queue)
+
+	for frame := range w.queue {
+		frame.Release()
+	}
+
 	close(w.done)
 
 	return nil
@@ -174,7 +176,6 @@ func (w *FrameWriter) Flush() {
 	w.flushBatchLocked()
 }
 
-// EnableHeartbeat enables automatic heartbeat sending in the write loop.
 func (w *FrameWriter) EnableHeartbeat(interval time.Duration, callback func() *Frame) {
 	w.mu.Lock()
 	w.heartbeatInterval = interval
@@ -185,11 +186,9 @@ func (w *FrameWriter) EnableHeartbeat(interval time.Duration, callback func() *F
 	select {
 	case w.heartbeatControl <- struct{}{}:
 	default:
-		// Channel already has a pending signal, no need to send another
 	}
 }
 
-// DisableHeartbeat disables automatic heartbeat sending.
 func (w *FrameWriter) DisableHeartbeat() {
 	w.mu.Lock()
 	w.heartbeatEnabled = false
@@ -198,6 +197,5 @@ func (w *FrameWriter) DisableHeartbeat() {
 	select {
 	case w.heartbeatControl <- struct{}{}:
 	default:
-		// Channel already has a pending signal, no need to send another
 	}
 }