[ZODB-Dev] know the state of an object

[Tim Peters]

[Chris Withers, about getting at the collection of modified objects]
> How hard would it be to expose?

The coding would be trivial in ZODB 3.6 (earliest version a new feature
could land) if limited solely to Connection objects.  More work to specify
the interface and write tests.

> Would there be any performance implications?

None from just from exposing the current Connection._registered_objects
implementation detail via an official API.

Whether that would be suitable for all intended purposes I don't know -- I
haven't seen detailed use cases.

Doubt it's a good idea regardless.  As Jim wrote, "things like this"
_should_ be approached not by adding an endless number of new APIs, but by
introducing an event system.  I don't know what the performance implications
of that may be, since ZODB has nothing like it at present.