SILC_FSM_EVENT_SIGNAL(event)

    Signals the `event' and awakens everybody that are waiting for this
    event.  This macro never blocks.  It can be safely called at any place
    in state function and in asynchronous callbacks or other functions.

    SILC_FSM_STATE(silc_foo_async_completion)
    {
      ...

      // Notify all waiters
      ctx->async_success = TRUE;
      SILC_FSM_EVENT_SIGNAL(ctx->async_event);
      ...
    }