feat: add Hijack()

pkg/websocket/conn.go

@@ -252,7 +252,6 @@ type Conn struct {
 	writeBufSize  int
 	writeDeadline time.Time
 	writer        io.WriteCloser // the current writer returned to the application
-	isWriting     bool           // for best-effort concurrent write detection
 
 	writeErrMu sync.Mutex
 	writeErr   error
@@ -613,18 +612,8 @@ func (w *messageWriter) flushFrame(final bool, extra []byte) error {
 	// concurrent writes. See the concurrency section in the package
 	// documentation for more info.
 
-	if c.isWriting {
-		panic("concurrent write to websocket connection")
-	}
-	c.isWriting = true
-
 	err := c.write(w.frameType, c.writeDeadline, c.writeBuf[framePos:w.pos], extra)
 
-	if !c.isWriting {
-		panic("concurrent write to websocket connection")
-	}
-	c.isWriting = false
-
 	if err != nil {
 		return w.endMessage(err)
 	}
@@ -741,16 +730,8 @@ func (c *Conn) WritePreparedMessage(pm *PreparedMessage) error {
 	if err != nil {
 		return err
 	}
-	if c.isWriting {
-		panic("concurrent write to websocket connection")
-	}
-	c.isWriting = true
-	err = c.write(frameType, c.writeDeadline, frameData, nil)
-	if !c.isWriting {
-		panic("concurrent write to websocket connection")
-	}
-	c.isWriting = false
-	return err
+
+	return c.write(frameType, c.writeDeadline, frameData, nil)
 }
 
 // WriteMessage is a helper method for getting a writer using NextWriter,