@AfterClass
  public static void tearDownAfterClass() throws Exception {
    Closeables.close(ASYNC_CONN, true);
    assertTrue(ASYNC_CONN.isClosed());
    TEST_UTIL.shutdownMiniCluster();
  }
Fix an infinite loop in {@link AsyncNonMetaRegionLocator}, see the comments on HBASE-21943 for
more details.
hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableLocateRegionForDeletedTable.java