我想在golang中使用劫持，而在客户端上收到无效响应

I want to use hijack in golang, while recieve invalid response on client

func hijack(w http.ResponseWriter, r *http.Request) {
    fmt.Println("start")

    hj, ok := w.(http.Hijacker)

    fmt.Println(ok)

    c, buf, err := hj.Hijack()
    if err != nil {
        panic(err)
    }
    n, err := buf.Write([]byte("hello"))
    if err != nil {
        panic(err)
    }

    fmt.Println("n == ",n)

    err = buf.Flush()
    if err != nil {
        panic(err)
    }

    fmt.Println("end")
}

follow printed on server:

start

true

n ==  5

end

but I got following error on the client

localhost sent an invalid response. ERR_INVALID_HTTP_RESPONSE

As the Hijacker's documentation says

Hijack lets the caller take over the connection. After a call to Hijack the HTTP server library will not do anything else with the connection.
It becomes the caller's responsibility to manage and close the connection.
The returned net.Conn may have read or write deadlines already set, depending on the configuration of the Server. It is the caller's responsibility to set or clear those deadlines as needed.
The returned bufio.Reader may contain unprocessed buffered data from the client.
After a call to Hijack, the original Request.Body must not be used. The original Request's Context remains valid and is not canceled until the Request's ServeHTTP method returns.

You need to write to c rather than buf. And you need to write response status and Content-Length header.

http.HandleFunc("/", func(writer http.ResponseWriter, request *http.Request) {
    fmt.Println("start")

    writer.Header().Add("Content-Length", "5")
    writer.WriteHeader(200)
    hj, ok := writer.(http.Hijacker)

    fmt.Println(ok)

    c, _, err := hj.Hijack()
    if err != nil {
        panic(err)
    }
    n, err := c.Write([]byte("hello"))
    if err != nil {
        panic(err)
    }

    fmt.Println("n == ",n)

    err = c.Close()
    if err != nil {
        panic(err)
    }

    fmt.Println("end")
})