chore(poller): Add poller package

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

poller/thread.go

@@ -0,0 +1,24 @@
+package poller
+
+import "sync"
+
+type routineGroup struct {
+	waitGroup sync.WaitGroup
+}
+
+func newRoutineGroup() *routineGroup {
+	return new(routineGroup)
+}
+
+func (g *routineGroup) Run(fn func()) {
+	g.waitGroup.Add(1)
+
+	go func() {
+		defer g.waitGroup.Done()
+		fn()
+	}()
+}
+
+func (g *routineGroup) Wait() {
+	g.waitGroup.Wait()
+}