问一个关于http: multiple response.WriteHeader calls 错误的问题

首先，我使用了github.com/ant0ine/go-json-rest/rest 这个包

直接贴代码

func Start(){

        NeptuneLog := logs.New()
        api := rest.NewApi()
        api.Use(rest.DefaultDevStack...)
        router, err := rest.MakeRouter(
                rest.Get("/:type/:action", handle),
                rest.Post("/:type/:action", handle),
        )
        if err != nil {
                NeptuneLog.Fatal(err)
        }
        api.SetApp(router)
        NeptuneLog.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}

=================start 负责调用 handle ====================

func handle (w rest.ResponseWriter, r *rest.Request) {
        NeptuneLog := logs.New()
        t  := r.PathParam("type")
        if (t == "submit") {
                action := r.PathParam("action")
                submitNode := SubmitNode{R:r,W:w,Action:action}
                SubmitChan <- submitNode
                NeptuneLog.Printf("%v",w)
                //node := test11{Action:action}
                //w.WriteJson(node)
        } else if t  =="browser" {
                action := r.PathParam("action")
                browserNode := BrowserNode{R:r,W:w,Action:action}
                BrowserChan <- browserNode
        } else  {
                //w.WriteJson("not found")
        }
}

============= handle 负责把request 和 response 放到结构体，然后放到channel ============

func doSubmit () {

        NeptuneLog := logs.New()
        for item := range  SubmitChan{
                NeptuneLog.Println("111")
                node := test11{Action:item.Action}
                NeptuneLog.Printf("%v",node)
                NeptuneLog.Printf("%v",item.W)
                item.W.WriteJson(node)
                NeptuneLog.Printf("%v",item.W)
        }
}

=========== dosubmit 真正干活，负责从channel拿东西，然后返回 ======

调用之后，server打印出了

http: multiple response.WriteHeader calls

的错误

==========更新下最新进展 ========

我把打印的返回拿出来的

发现有 Conn.Write wrote more than the declared Content-Length 这个错误