Potential segfault on server statup about nuraft

[alesapin]

Also, I have a question. Is there any way from a user code to detect that the current server is ready to serve requests? By this, I mean that the server applied all uncommitted entries to its state machine and see the leader node or this node is the leader itself.
Seems like neither BecomeLeader nor BecomeFresh are not reliable ways to detect it.

[greensky00]

@alesapin
There is is_initialized() API to check if the Raft is ready (either it becomes leader or receives the first heartbeat from the existing leader). But that won't be the case for you if your background thread is doing something with raft_server before the constructor is done. We also internally use an atomic flag, running for example:

raftServer = cs_new<raft_server>(ctx, i_opt);
...
running = true;

but that is not the part of Raft. I think your PR #195 seems reasonable to avoid the issue without maintaining external flags.

[alesapin]

Thanks, let's close this one.