start a goroutine to clear expired workers when init a pool

pool.go

@@ -96,7 +96,7 @@ func NewPool(size, expiry int) (*Pool, error) {
 		release:    make(chan sig, 1),
 		expiryDuration: time.Duration(expiry)*time.Second,
 	}
-
+	p.monitorAndClear()
 	return p, nil
 }
 

pool_func.go

@@ -97,7 +97,7 @@ func NewPoolWithFunc(size, expiry int, f pf) (*PoolWithFunc, error) {
 		expiryDuration: time.Duration(expiry)*time.Second,
 		poolFunc:   f,
 	}
-
+	p.MonitorAndClear()
 	return p, nil
 }