int n = handle.sendrecv(new byte[10], 0, 0, new byte[20], 100);
        assertEquals(0, n, "Default response length is 0 unless protocol fills it");
    }

    @Test
    @DisplayName("sendrecv uses CallNamedPipe when PIPE_TYPE_CALL is set")
    void sendrecv_call_branch() throws Exception {
        int type = SmbPipeResource.PIPE_TYPE_CALL | SmbPipeResource.PIPE_TYPE_RDWR;