leader stop send heartbeat to follower

[david-ealge-han]

Describe the bug

A clear and concise description of what the bug is.

Expected behavior

leader send heartbeat to follower periodically

Actual behavior

leader stop send heartbeat to follower

Steps to reproduce

Minimal yet complete reproducer code (or GitHub URL to code)

when try-lock failed, heartbeat error put into the list, may need next unlock to run the heartbeat, so the heartbeat cann't send periodically as expected. this may cause leader vote.

Environment

• SOFAJRaft version: jraft-core-1.2.7.beta1.jar
• JVM version (e.g. java -version):
• OS version (e.g. uname -a):
• Maven version:
• IDE version:

[killme2008]

Yep, there is a race condition between

  this.pendingErrors.add(errorCode);

and ThreadId#unlock, so the error signal may be delayed and cause an unnecessary election.

We wil fix it, thank your for your report.