I haven't read the code, so I can't comment on how and
when FastLeaderElection works(Maybe it is some kind of
optimization and won't be able to handle catastrophic failures, just a wild
BTW I want to ask how the ZAB protocol works in the following situation:
Suppose a ZK cluster consists of 5 nodes(A,B,C,D,E). Leader A proposed a
case a) A,B logged successfully, quorum not reached, commit should fail.
case b) A,B,C logged successfully, quorum has been reached, commit should
Now A crashed and went away, how the new leader distinguish case a> and case
b> since neither of them(B or B+C) has reached the quorum?