When a Raft API call such as `add_entry`, `set_configuration` or
`modify_config` takes too long, we need to time-out. There was no way to
abort these calls previously so we would do that by discarding the futures.
Recently the APIs were extended with `abort_source` parameters. Use this.
Also improve debuggability if the functions throw an exception type that
we don't expect. Previously if they did, a cryptic assert would fail
somewhere deep in the generator code, making the problem hard to debug.
Also collect some statistics in the test about the number of successful
and failed ops. I used it to manually check whether there was a
difference in how often operations fail with using the out timeout
method and the new timeout method (there doesn't seem to be any).
* kbr/nemesis-abort-source:
test: raft: randomized_nemesis_test: on timeout, abort calls instead of discarding them
raft: server: translate semaphore_aborted to request_aborted
test: raft: logical_timer: add abortable version of `sleep_until`
test: raft: randomized_nemesis_test: collect statistics on successful and failed ops
9c96a37143