fix: connection.go

pkg/mqtt/connection.go

@@ -315,6 +315,8 @@ func (c *Connection) RcvMsgFromClient() {
 }
 
 func (c *Connection) SendMsgToClient() {
+	c.mLock.Lock()
+	c.mLock.Unlock()
 	if c.Conn == nil {
 		return
 	}

pkg/mqtt/message.go

@@ -114,7 +114,7 @@ func (hdr *Header) EncodeInto(buf *bytes.Buffer, msgType TagMessageType, remaini
 	}
 
 	val := byte(msgType) << 4
-	val |= (boolToByte(hdr.DupFlag) << 3)
+	val |= boolToByte(hdr.DupFlag) << 3
 	val |= byte(hdr.QosLevel) << 1
 	val |= boolToByte(hdr.Retain)
 	buf.WriteByte(val)