From 3620ebfc1114e967b3a12838718baab8e2d261a1 Mon Sep 17 00:00:00 2001
From: Darien Raymond <admin@v2ray.com>
Date: Thu, 7 Jun 2018 06:38:45 +0200
Subject: [PATCH] optimize for small number of tasks

---
 common/task/task.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/common/task/task.go b/common/task/task.go
index 72f327ef2..e1640eac7 100644
--- a/common/task/task.go
+++ b/common/task/task.go
@@ -56,6 +56,15 @@ func Parallel(tasks ...Task) ExecutionOption {
 
 func Sequential(tasks ...Task) ExecutionOption {
 	return func(c *executionContext) {
+		if len(tasks) == 0 {
+			return
+		}
+
+		if len(tasks) == 1 {
+			c.tasks = append(c.tasks, tasks[0])
+			return
+		}
+
 		c.tasks = append(c.tasks, func() error {
 			return execute(tasks...)
 		})