How to SendEvent properly?

[RangerCD]

I'm trying to maximize a window with xproto.SendEvent, just like command wmctrl -ir xxxxxx -b add,maximized_vert,maximized_horz:

func X11Atom(X *xgb.Conn, name string) (xproto.Atom, error) {
	reply, err := xproto.InternAtom(X, false, uint16(len(name)), name).Reply()
	if err != nil {
		return 0, err
	}
	return reply.Atom, nil
}

func MaximizeWindow(window xproto.Window) error {
	setup := xproto.Setup(X)
	root := setup.DefaultScreen(X).Root

	stateAtom, err := X11Atom(X, "_NET_WM_STATE")
	if err != nil {
		return err
	}
	maxHorzAtom, err := X11Atom(X, "_NET_WM_STATE_MAXIMIZED_HORZ")
	if err != nil {
		return err
	}
	maxVertAtom, err := X11Atom(X, "_NET_WM_STATE_MAXIMIZED_VERT")
	if err != nil {
		return err
	}

	err = xproto.SendEventChecked(X, false, root, xproto.EventMaskSubstructureRedirect|xproto.EventMaskSubstructureNotify,
		xproto.ClientMessageEvent{
			Sequence: 0,
			Format:   32,
			Window:   window,
			Type:     stateAtom,
			Data: xproto.ClientMessageDataUnionData32New([]uint32{
				1, // _NET_WM_STATE_ADD
				uint32(maxHorzAtom),
				uint32(maxVertAtom),
				0,
				0,
			}),
		}.String()).Check()
	if err != nil {
		return err
	}
	X.Sync()

	return nil
}

I'm pretty sure window is the correct one, but nothing happened to that window, So I have to implement this with C:

/*
#cgo linux pkg-config: x11

#include <string.h>
#include <X11/Xlib.h>
#include <X11/Xatom.h>

int MaximizeWindow(Display *display, Window window) {
	Atom stateAtom = XInternAtom(display, "_NET_WM_STATE", False);
	Atom maxHorzAtom = XInternAtom(display, "_NET_WM_STATE_MAXIMIZED_HORZ", False);
	Atom maxVertAtom = XInternAtom(display, "_NET_WM_STATE_MAXIMIZED_VERT", False);

	XEvent e;
	memset(&e, 0, sizeof(e));
	e.xclient.type = ClientMessage;
	e.xclient.window = window;
	e.xclient.message_type = stateAtom;
	e.xclient.format = 32;
	e.xclient.data.l[0] = 1; // _NET_WM_STATE_ADD
	e.xclient.data.l[1] = maxHorzAtom;
	e.xclient.data.l[2] = maxVertAtom;
	e.xclient.data.l[3] = 0;
	e.xclient.data.l[4] = 0;

	XSendEvent(display, DefaultRootWindow(display), False,
		SubstructureRedirectMask | SubstructureNotifyMask, &e);

	XSync(display, False);

	return 0;
}

*/
import "C"

func MaximizeWindow(window xproto.Window) error {
	display := C.XOpenDisplay(nil)
	defer C.XCloseDisplay(display)
	C.MaximizeWindow(display, C.ulong(window))

	return nil
}

And it works just fine.
I've checked window event with xprop -spy -id xxxxxx, nothing comes in with golang version. But with C version, there is an event:

_NET_WM_STATE(ATOM) = _NET_WM_STATE_MAXIMIZED_VERT, _NET_WM_STATE_MAXIMIZED_HORZ, _NET_WM_STATE_FOCUSED

So I think there must be something wrong with previous golang version.
I've tried both SendEvent and SendEventChecked, with Reply() or Check(), still not working.
But I couldn't find anything helpful on the Internet, any idea?