fix: stop creating goroutines if context is already canceled

waku/v2/api/missing/missing_messages.go

@@ -144,6 +144,13 @@ func (m *MissingMessageVerifier) fetchHistory(c chan<- *protocol.Envelope, inter
 			j = len(contentTopics)
 		}
 
+		select {
+		case <-interest.ctx.Done():
+			return
+		default:
+			// continue...
+		}
+
 		now := m.timesource.Now()
 		err := m.fetchMessagesBatch(c, interest, i, j, now)
 		if err != nil {
@@ -260,6 +267,13 @@ func (m *MissingMessageVerifier) fetchMessagesBatch(c chan<- *protocol.Envelope,
 			j = len(missingHashes)
 		}
 
+		select {
+		case <-interest.ctx.Done():
+			return nil
+		default:
+			// continue...
+		}
+
 		wg.Add(1)
 		go func(messageHashes []pb.MessageHash) {
 			defer wg.Wait()