constructor(type, status = undefined) {
    /** @const {!ModuleLoadFailure.Type} */
    this.type = type;
    /** @const {number|undefined} */
    this.status = status;
  }
@param {!ModuleLoadFailure.Type} type
@param {number=} status Optional http error status associated with this
    failure. This should be `undefined` if there was no associated http
    error status (i.e. do not use values like -1).