refactor: use defer

cmd/messages_text.go

@@ -599,11 +599,11 @@ func (mt *MessagesText) setFetchingChunk(value bool) {
 
 func (mt *MessagesText) waitForChunkEvent() {
 	mt.fetchingMembers.mu.Lock()
+	defer mt.fetchingMembers.mu.Unlock()
+
 	if !mt.fetchingMembers.value {
-		mt.fetchingMembers.mu.Unlock()
 		return
 	}
-	mt.fetchingMembers.mu.Unlock()
 
 	select {
 	case <-mt.fetchingMembers.done: