Move reflect fn value out of loop

Author: vardius

go.mod

@@ -1 +1,3 @@
 module github.com/vardius/worker-pool
+
+go 1.12

pool.go

@@ -39,9 +39,8 @@ func (p *pool) Start(maxWorkers int, fn interface{}) error {
 		return fmt.Errorf("Can not start already stopped worker")
 	}
 
+	h := reflect.ValueOf(fn)
 	for i := 1; i <= maxWorkers; i++ {
-		h := reflect.ValueOf(fn)
-
 		go func() {
 			for args := range p.queue {
 				h.Call(args)