通过Mac OS10.9.5上的Golang http服务器进行对等连接重置

I got an weird error when writing some stress tests on a golang web application. Here is the code for web server

package httptest

import (
    "net/http"
    "testing"
)

func TestHttpTest(t *testing.T) {
    http.HandleFunc("/", func(res http.ResponseWriter, req *http.Request) {
        //<-time.After(2 * time.Second)
    })
    http.ListenAndServe(":2222", nil)
}

When I run go test ./... and use ApacheBench to perform stress test:

ab -c 200 -n 1000 http://localhost:2222/123

It gives me following error randomly:

Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking localhost (be patient)
Completed 100 requests
Completed 200 requests
apr_socket_recv: Connection reset by peer (54)
Total of 235 requests completed

I am running the test on Mac OS 10.9. The ulimit of the os is setting as unlimited. Does anyone meet the same problem?