golang 怎么重写标准库内的代码呢

如果是第三方库的话一般就直接 down 下来魔改了，但是 go 的标准库怎么操作呢？

net/http/transport.go

的 transport 只实现了 proxy 的 socks5 、http 、https

func (t *Transport) dialConn(ctx context.Context, cm connectMethod) (pconn *persistConn, err error) {
	// 省略
    // Proxy setup.
	switch {
	case cm.proxyURL == nil:
		// Do nothing. Not using a proxy.
	case cm.proxyURL.Scheme == "socks5":
		conn := pconn.conn
		d := socksNewDialer("tcp", conn.RemoteAddr().String())
		if u := cm.proxyURL.User; u != nil {
			auth := &socksUsernamePassword{
				Username: u.Username(),
			}
			auth.Password, _ = u.Password()
			d.AuthMethods = []socksAuthMethod{
				socksAuthMethodNotRequired,
				socksAuthMethodUsernamePassword,
			}
			d.Authenticate = auth.Authenticate
		}
		if _, err := d.DialWithConn(ctx, conn, "tcp", cm.targetAddr); err != nil {
			conn.Close()
			return nil, err
		}
	case cm.targetScheme == "http":
		pconn.isProxy = true
		if pa := cm.proxyAuth(); pa != "" {
			pconn.mutateHeaderFunc = func(h Header) {
				h.Set("Proxy-Authorization", pa)
			}
		}
	case cm.targetScheme == "https":
		conn := pconn.conn
		var hdr Header
		if t.GetProxyConnectHeader != nil {
			var err error
			hdr, err = t.GetProxyConnectHeader(ctx, cm.proxyURL, cm.targetAddr)
			if err != nil {
				conn.Close()
				return nil, err
			}
		} else {
			hdr = t.ProxyConnectHeader
		}
		if hdr == nil {
			hdr = make(Header)
		}
		if pa := cm.proxyAuth(); pa != "" {
			hdr = hdr.Clone()
			hdr.Set("Proxy-Authorization", pa)
		}
		connectReq := &Request{
			Method: "CONNECT",
			URL:    &url.URL{Opaque: cm.targetAddr},
			Host:   cm.targetAddr,
			Header: hdr,
		}
}

Python 话一般继承后重写就 ok 了

golang 的话 函数参数首字母也是小写的，外部也不能调用。。。