golang http服务器不接受发布大数据(golang http server does not accept post large data)

At current time try use golang http server and compile it from this code:

    package main

import (
    "io"
    "net/http"
    "time"
)

func hello(w http.ResponseWriter, r *http.Request) {
    r.ParseForm()
    io.WriteString(w, "Hello world!")
}

var mux map[string]func(http.ResponseWriter, *http.Request)

func main() {
    server := http.Server{
        Addr:           ":8000",
        MaxHeaderBytes: 30000000,
        ReadTimeout:    10 * time.Second,
        WriteTimeout:   10 * time.Second,
        Handler:        &myHandler{},
    }

    mux = make(map[string]func(http.ResponseWriter, *http.Request))
    mux["/"] = hello

    server.ListenAndServe()
}

type myHandler struct{}

func (*myHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    if h, ok := mux[r.URL.String()]; ok {
        h(w, r)
        return
    }

    io.WriteString(w, "My server: "+r.URL.String())
}

Runs it and send test data via Apache Bench

ab.exe -c 30 -n 1000 -p ESServer.exe -T application/octet-stream http://localhost:8000/ 

It's working excelent with small files but ESServer.exe has size 8Mb and I'm receiving next error "apr_socket_recv: An existing connection was forcibly closed by the remote host. (730054)."

What problem may happens?