This adds the capability to the segment-verify tool of checking all
pieces of every indicated segment.
Pieces which could not be accessed (i.e. we couldn't get a single
byte from them) are recorded in a csv file.
I haven't been able to test this in any very meaningful way, yet, but I
am comforted by the fact that the worst things it could possibly do are
(a) download pieces too many times, and (b) miss downloading some
pieces.
Change-Id: I3aba30921572c974993363eb36d0fd5b3ae97907
It's quite likely to hit some timelimit, rather than giving up
immediately, let's retry after the throttle amount.
Change-Id: I20944b058d771f5d4bfa0eea7a2c26cefcd74739
* Disallow too large listing limit, which would cause a lot of memory to
be consumed.
* Fix throttling logic and add a test.
* Fix read error handling; depending on the concurrency it can return
the NotFound status either in the Read or Close.
Change-Id: I778f04a5961988b2480df5c7faaa22393fc5d760
