feat: Waku v2 bridge

Issue #12610

vendor/github.com/anacrolix/missinggo/flag.go

@@ -0,0 +1,41 @@
+package missinggo
+
+import "sync"
+
+// Flag represents a boolean value, that signals sync.Cond's when it changes.
+// It's not concurrent safe by intention.
+type Flag struct {
+	Conds map[*sync.Cond]struct{}
+	value bool
+}
+
+func (me *Flag) Set(value bool) {
+	if value != me.value {
+		me.broadcastChange()
+	}
+	me.value = value
+}
+
+func (me *Flag) Get() bool {
+	return me.value
+}
+
+func (me *Flag) broadcastChange() {
+	for cond := range me.Conds {
+		cond.Broadcast()
+	}
+}
+
+func (me *Flag) addCond(c *sync.Cond) {
+	if me.Conds == nil {
+		me.Conds = make(map[*sync.Cond]struct{})
+	}
+	me.Conds[c] = struct{}{}
+}
+
+// Adds the sync.Cond to all the given Flag's.
+func AddCondToFlags(cond *sync.Cond, flags ...*Flag) {
+	for _, f := range flags {
+		f.addCond(cond)
+	}
+}