Nested connections try to clean up themselves multiple
times. This does not work

see https://github.com/zopefoundation/ZODB/issues/16

see https://github.com/zopefoundation/ZODB/issues/16

when objects had been added in readCurrent

still need to come up with a test

string representation.

https://bugs.launchpad.net/zodb/+bug/993350

  Conflict resolution failed when state included cross-database
  persistent references with classes that couldn't be imported.

the fix fix.

  Conflict resolution failed when state included persistent references
  with classes that couldn't be imported.

"Blob temp file get's removed before it should",
https://bugs.launchpad.net/zodb/+bug/595378

A way this to happen is that a transaction is aborted after the
commit process has started. I don't know how this would happen in
the wild.

In 3.10.3, the ZEO tpc_abort call to the server is changed to be
synchronous, which should address this case. Maybe there's another
case.

----------

- "activity monitor not updated for subconnections when connection
  returned to pool"

https://bugs.launchpad.net/zodb/+bug/737198

difference.

Simplified and optimized marshalling code.

MRUish.

In some experiments, this led to significant reductions in cache miss
rates.

Fixed typo in comment