How to use the @xviz/schema.MessageTypes.STATE_UPDATE function in @xviz/schema

validator.onConnect();
  validator.onStart({
    version: '2.0.0',
    session_type: 'LIVE' // eslint-disable-line camelcase
  });
  validator.onMetadata({version: '2.0.0'});
  validator.onStateUpdate(MINIMAL_STATE_UPDATE);
  validator.onStateUpdate(MINIMAL_STATE_UPDATE);

  const s = validator.stats;

  const e = {};
  e[MessageTypes.METADATA] = 1;
  e[MessageTypes.START] = 1;
  e[MessageTypes.STATE_UPDATE] = 2;

  t.deepEqual(s.messages, e, 'got all messages');
  t.deepEqual(s.validationErrors, {}, 'all valid');
  t.deepEqual(s.stateErrors, {}, 'valid transitions');
  t.end();
});

validator.onTransformLog({
    id: '9a71050b-4143-479e-8700-36ec2ed8670a'
  });
  validator.onStateUpdate(MINIMAL_STATE_UPDATE);
  validator.onStateUpdate(MINIMAL_STATE_UPDATE);
  validator.onTransformLogDone({
    id: '9a71050b-4143-479e-8700-36ec2ed8670a'
  });

  const s = validator.stats;

  const e = {};
  e[MessageTypes.METADATA] = 1;
  e[MessageTypes.START] = 1;
  e[MessageTypes.TRANSFORM_LOG] = 1;
  e[MessageTypes.STATE_UPDATE] = 2;
  e[MessageTypes.TRANSFORM_LOG_DONE] = 1;

  t.deepEqual(s.messages, e, 'got all messages');
  t.deepEqual(s.validationErrors, {}, 'all valid');
  t.deepEqual(s.stateErrors, {}, 'valid transitions');
  t.end();
});