@Override
  protected void after() {
    try {
      testingUtility.shutdownMiniCluster();
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }
Create a {@link AsyncConnection} to the managed {@link SingleProcessHBaseCluster}. It's up to
the caller to {@link AsyncConnection#close() close()} the connection when finished.
hbase-server/src/test/java/org/apache/hadoop/hbase/MiniClusterRule.java