@Override
    public void fromData(DataInput in,
        DeserializationContext context) throws IOException, ClassNotFoundException {
      super.fromData(in, context);
      this.context = ClientProxyMembershipID.readCanonicalized(in);
    }
Creates a new {@code RegistrationContextMessage} that broadcasts that the given
{@code Instantiator} was registered.
geode-core/src/main/java/org/apache/geode/internal/InternalInstantiator.java