wip: raft does not care about migrating
wip: optimize code
wip: raft election
wip
wip: fix raft leader missing log entries
wip
fix a dead lock
batch set slot route
wip: raft persist
wip
refactor cluster suite
remove relay
rename relay2
refactor: allow customizing client factory
test raft
refactor re-balance
avoid errors caused by inconsistent status on follower nodes during raft commits
test raft election