* We don't necessarily want to always call ClearAll when using
MessageHistory since it also removes the MessageTrackListener from
each of the IMessagingHubs.
* Expose ClearHistory (previously a private method called clearData)
@jeremydmiller I've got some tests around this, but are there any other tests you can think of that I should write for this?
Expose way to clear history from MessageHistory
@jeremydmiller I've got some tests around this, but are there any other tests you can think of that I should write for this?