t.Helper()
	if !supportsSendfile {
		f()
		return
	}
	orig := poll.TestHookDidSendFile
	defer func() {
		poll.TestHookDidSendFile = orig
	}()
	var (
		called     bool
		gotHandled bool
		gotFD      *poll.FD
	)
	poll.TestHookDidSendFile = func(dstFD *poll.FD, src int, written int64, err error, handled bool) {
		if called {