diff --git a/servlet.go b/servlet.go
index 7317842..2574b8c 100644
--- a/servlet.go
+++ b/servlet.go
@@ -39,6 +39,8 @@ type rpcServlet struct {
 
 	stopChan chan struct{}
 	stopWg   sync.WaitGroup
+
+	sendMtx sync.RWMutex
 }
 
 func (s *rpcServlet) Context() ServletContext {
@@ -83,6 +85,7 @@ func (s *rpcServlet) Start(parentCTX cuc.Context, conn interface{}, doneChan cha
 }
 
 func (s *rpcServlet) Send(method string, args ...interface{}) (err error) {
+	s.sendMtx.RLock()
 	noti := &notification{
 		method: method,
 		args:   args,
@@ -92,7 +95,7 @@ func (s *rpcServlet) Send(method string, args ...interface{}) (err error) {
 	}
 
 	s.responseQueueChan <- rs
-
+	s.sendMtx.RUnlock()
 	return nil
 }