Computing the snapshot file path is error prone; snapshot recovery was
constructing file paths missing a path separator so the snapshot
would never be loaded. Instead, refactor the backend path handling
to use helper functions where possible.
Provides two implementations of Recorder-- one that is non-blocking
like the original version and one that provides a blocking channel
to avoid busy waiting or racing in tests when no other synchronization
is available.
It is safe to repair the unexpectedEOF error in the last wal. raft
will not send out message before the entry successfully comitted
into wal. Thus we can safely truncate the last entry in the wal
to repair.
WAL should control the cut logic itself. We want to do falloc to
per allocate the space for a segmented wal file at the beginning
and cut it when it size reaches the limit.
