feat: Waku v2 bridge

Issue #12610

vendor/github.com/libp2p/go-libp2p-pubsub/timecache/util.go

@@ -0,0 +1,35 @@
+package timecache
+
+import (
+	"context"
+	"sync"
+	"time"
+)
+
+var backgroundSweepInterval = time.Minute
+
+func background(ctx context.Context, lk sync.Locker, m map[string]time.Time) {
+	ticker := time.NewTicker(backgroundSweepInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case now := <-ticker.C:
+			sweep(lk, m, now)
+
+		case <-ctx.Done():
+			return
+		}
+	}
+}
+
+func sweep(lk sync.Locker, m map[string]time.Time, now time.Time) {
+	lk.Lock()
+	defer lk.Unlock()
+
+	for k, expiry := range m {
+		if expiry.Before(now) {
+			delete(m, k)
+		}
+	}
+}