RATIS-1399. should notify all the log senders Asynchronously

[JacksonYao287]

What changes were proposed in this pull request?

//LeaderStateImpl.java

void notifySenders() {
  senders.forEach(LogAppender::notifyLogAppender);
}

if raft , one slow log sender should not block others sender

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/RATIS-1399

How was this patch tested?

no need

[JacksonYao287]

@szetszwo @bshashikant @guihecheng PTAL!

[szetszwo]

@JacksonYao287 , the change looks good. Have you tested it?

[JacksonYao287]

@szetszwo thanks for the review, i think the logic here is correct, and i will test it in my cluster to confirm it

[guihecheng]

LGTM

[szetszwo]

..., and i will test it in my cluster to confirm it

@JacksonYao287 , have you got a chance to test it?

[JacksonYao287]

@szetszwo i have tested this patch. i start a scm first(leader), but i find a problem when the second raft peer start(follower) that it will fail to install snapshot. i am investigating this issue. do you have any idea about this? i open a jira for this issue
https://issues.apache.org/jira/browse/RATIS-1402

[JacksonYao287]

@szetszwo hi, we have tested this patch and it works as expected, the performance does not downgrade again when a follower crashes. seems we can merge this patch now.

[szetszwo]

@szetszwo i have tested this patch. i start a scm first(leader), but i find a problem when the second raft peer start(follower) that it will fail to install snapshot. i am investigating this issue. do you have any idea about this? i open a jira for this issue
https://issues.apache.org/jira/browse/RATIS-1402

Sorry that I don't aware this problem. As you mentioned in RATIS-1402, it probably was caused by RATIS-1399.

[JacksonYao287]

Sorry that I don't aware this problem. As you mentioned in RATIS-1402, it probably was caused by RATIS-1399.

no , i think it is caused by RATIS-1390 not RATIS-1399. when i test this patch , i revert RATIS-1390. i will try to fix it in RATIS-1402.

thanks @szetszwo for the review and @guihecheng for the great work