static async dumpJSON(name, dummyArrayBuffers) {
    const savedDatabase = await this.dump(name);
    const replacer =
        (key, value) => this.replacer_(dummyArrayBuffers || false, key, value);
    return JSON.stringify(savedDatabase, replacer);
  }
@param {string} name The name of the database to dump.
@param {boolean=} dummyArrayBuffers If true, replace array buffer data with
  dummy data, as you might want for generating unit test data. Defaults to
  false.
@return {!Promise<string>} A JSON string that can be used to recreate the
  database later in a call to restoreJSON().