chore: remove mutexes

pkg/core/track.go

@@ -149,19 +149,12 @@ func (s *Sender) Start() {
 }
 
 func (s *Sender) Wait() {
-	s.mu.Lock()
-	done := s.done
-	s.mu.Unlock()
-
-	if done != nil {
+	if done := s.done; done != nil {
 		<-done
 	}
 }
 
 func (s *Sender) State() string {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-
 	if s.buf == nil {
 		return "closed"
 	}