ECHO_STATE_STARTED
stream->state |= ECHO_STATE_STARTED;
stream->state &= ~ECHO_STATE_STARTED;
if ((stream->state & ECHO_STATE_STARTED) == 0 ||
if ((stream->state & ECHO_STATE_STARTED) != 0)
(pstream->state & ECHO_STATE_STARTED) == 0)
(rstream->state & ECHO_STATE_STARTED) == 0)