This method should not effect other stages by sending commands etc unless it creates them. It
is not impossible that the stage will receive other commands besides Connected before this
method is called. It is not impossible for this method to be called multiple times by
misbehaving stages. It is therefore recommended that the method be idempotent.
Shuts down the stage, deallocating resources, etc.
Shuts down the stage, deallocating resources, etc.
It will be called when the stage receives a Disconnected command unless inboundCommand
is overridden. This method should not send or Disconnected commands.
It is possible that this will not be called due to failure of other stages to propagate
shutdown commands. Conversely, it is also possible for this to be called more than once due to
the reception of multiple shutdown commands. It is therefore recommended that the method be
idempotent.