[MERGE/RFC] "bzr branch" opens the source branch twice, and the pack-names 12 times

[Martin Pool]

Just a question from while I was merging this (the precise lines are
from my conflict resolution so they're not verbatim from your patch):

        elif self._file is None:
            data_ranges = self._transport.readv(self._name, ranges)
        else:
            data_ranges = []
            for offset, size in ranges:
                self._file.seek(offset)
                data_ranges.append((offset, self._file.read(size)))

Did you find that using a python file directly was substantially
faster than using a transport object?  It would be nice to provide
apis there that map through to something just as fast.

-- 
Martin <http://launchpad.net/~mbp/>