@Override
  public ProcedureEvent<?> getInitializedEvent() {
    return initialized;
  }
Mainly used in procedure related tests, where we will restart ProcedureExecutor and
AssignmentManager, but we do not want to restart master(to speed up the test), so we need to
disable rpc for a while otherwise some critical rpc requests such as
reportRegionStateTransition could fail and cause region server to abort.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java