refactor project structure

lib/sync/wait/wait.go

@@ -0,0 +1,38 @@
+package wait
+
+import (
+	"sync"
+	"time"
+)
+
+type Wait struct {
+	wg sync.WaitGroup
+}
+
+func (w *Wait) Add(delta int) {
+	w.wg.Add(delta)
+}
+
+func (w *Wait) Done() {
+	w.wg.Done()
+}
+
+func (w *Wait) Wait() {
+	w.wg.Wait()
+}
+
+// return isTimeout
+func (w *Wait) WaitWithTimeout(timeout time.Duration) bool {
+	c := make(chan bool)
+	go func() {
+		defer close(c)
+		w.wg.Wait()
+		c <- true
+	}()
+	select {
+	case <-c:
+		return false // completed normally
+	case <-time.After(timeout):
+		return true // timed out
+	}
+}