@Override
  public void _readEssentialData(DataInput in,
      Function<InetAddress, String> hostnameResolver)
      throws IOException, ClassNotFoundException {
    memberIdentifier._readEssentialData(in, hostnameResolver);
  }
Returns this client member's durable attributes or null if no durable attributes were created.
geode-core/src/main/java/org/apache/geode/distributed/internal/membership/InternalDistributedMember.java