This allows subclasses to submit any queued events that have to be
handled before normal operation starts. For example, if an error event
got generated during initialization which has to be handled by the
state machine, the startup hook in the private class can be used to post
those events and have the state machine handle them appropriately.
Change-Id: I62249a31d8840f47bc19920870ad5da9647e61f9
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>