@Override
  public void toData(DataOutput out,
      SerializationContext context) throws IOException {
    out.writeInt(uniqId);
    InternalDataSerializer.invokeToData(memberId, out);
  }
Constructor for the Transation Manager, the birth place of TXId objects. The object is
Serializable mainly because of the identifier type provided by JGroups.
geode-core/src/main/java/org/apache/geode/internal/cache/TXId.java