private void assertCloseThenOpen() {
    assertEquals(closeSubmittedCount + 1, closeProcMetrics.getSubmittedCounter().getCount());
    assertEquals(closeFailedCount, closeProcMetrics.getFailedCounter().getCount());
    assertEquals(openSubmittedCount + 1, openProcMetrics.getSubmittedCounter().getCount());
    assertEquals(openFailedCount, openProcMetrics.getFailedCounter().getCount());
  }
It is possible that when AM send assign meta request to a RS successfully, but RS can not send
back any response, which cause master startup hangs forever
hbase-server/src/test/java/org/apache/hadoop/hbase/master/assignment/TestAssignmentManager.java