feat: Waku v2 bridge

Issue #12610

vendor/github.com/anacrolix/chansync/semaphore.go

@@ -0,0 +1,26 @@
+package chansync
+
+import (
+	"github.com/anacrolix/chansync/events"
+)
+
+// Channel semaphore, as is popular for controlling access to limited resources. Should not be used
+// zero-initialized.
+type Semaphore struct {
+	ch chan struct{}
+}
+
+// Returns an initialized semaphore with n slots.
+func NewSemaphore(n int) Semaphore {
+	return Semaphore{ch: make(chan struct{}, n)}
+}
+
+// Returns a channel for acquiring a slot.
+func (me Semaphore) Acquire() events.Acquire {
+	return me.ch
+}
+
+// Returns a channel for releasing a slot.
+func (me Semaphore) Release() events.Release {
+	return me.ch
+}