[feature] Add before close handler for consumers

[pandafy]

trafficstars

Add a before close handler which is only triggered when the connection was accepted in the first place. Such handler is useful for housekeeping.

[yedpodtrzitko]

maybe you can override close() in your consumer and do the housekeeping there before calling parent close() no?

[pandafy]

I was looking for something that is triggered only when the connection has already been accepted. Like disconnect method is called irrespective of whether connection was established or not.