[ZODB-Dev] Use of fsync in FileStorage

[Tim Peters]

[Tim Peters]
> This commits more-or-less "average size" transactions, but on the high
> side (about 2KB per transaction record).

Grr.  That was hallucination, caused by looking at a different Data.fs file.
It's actually committing transactions smaller than I was aiming at, closer
to 700 bytes/transaction.  Still, that's thoroughly typical if most of your
work consists of adding new keys to one IIBTree <wink>.