code: function createFake(name, obj) {
    obj = obj || {};
  
    // Only add property for type check.
    Object.defineProperty(obj, STRUCT_NAME_KEY, {
      value: name,
      wriatble: false,
      enumerable: false
    });
    return obj;
  }
docs: For no-check mode.
  
  @param {String} name Struct name.
  @param {Object} obj Base object (option).
  @return {Object} Fake struct object.