@Override
  public void readEssentialData(DataInput in,
      DeserializationContext context) throws IOException, ClassNotFoundException {
    setVersion(Versioning.getVersion(VersioningIO.readOrdinal(in)));

    int flags = in.readShort();
    networkPartitionDetectionEnabled = (flags & NPD_ENABLED_BIT) != 0;
    preferredForCoordinator = (flags & COORD_ENABLED_BIT) != 0;

    inetAddr = StaticSerialization.readInetAddress(in);
    if (inetAddr != null) {
      hostName = inetAddr.getHostAddress();
    }
    udpPort = in.readInt();
    vmViewId = in.readInt();
    uuidMSBs = in.readLong();
    uuidLSBs = in.readLong();
    if (context.getSerializationVersion().ordinal() >= KnownVersion.GEODE_1_2_0.ordinal()) {
      vmKind = in.readByte();
    }
    isPartial = true;
  }
checks to see if this address has UUID information needed to send messages via JGroups
geode-membership/src/main/java/org/apache/geode/distributed/internal/membership/gms/GMSMemberData.java