t.Error("internal/poll.SendFile did not handle the write, want it to")
		return
	}
	if &wantConn.(*TCPConn).fd.pfd != gotFD {
		t.Error("internal.poll.SendFile called with unexpected FD")
	}
}

func TestSendfile(t *testing.T) {
	ln := newLocalListener(t, "tcp")
	defer ln.Close()

	errc := make(chan error, 1)
	go func(ln Listener) {
		// Wait for a connection.
		conn, err := ln.Accept()
		if err != nil {