bundle2: inform transaction that we are in a bundle2 unbundle That way, hooks called during the unbundle process are aware that a bigger picture is going on.

changegroup: use tr.hookargs when calling changegroup hooks So that other parties using the transaction can put information in our hook calls.

changegroup: use tr.hookargs when calling pretxnchangegroup hooks So that other parties using the transaction can put information in our hook calls.

addchangegroup: register data in tr.hookargs We are registering data related to the process into the transaction hook data. This lets other parties using the same transaction get informed of the addchangegroup result.