private Optional<Method> getUniqKeyMethod() {
    try {
      return Optional.of(DFSOutputStream.class.getMethod("getUniqKey"));
    } catch (NoSuchMethodException e) {
      // should be hadoop 3.3 or below
      return Optional.empty();
    }
  }
Make sure lease renewal works. Since it is in a background thread, normal read/write test can not
verify it.
<p>
See HBASE-28955 for more details.
hbase-asyncfs/src/test/java/org/apache/hadoop/hbase/io/asyncfs/TestLeaseRenewal.java