async run(filepath, options = {}) {
    if (!filepath || typeof filepath !== 'string') {
      throw createInvalidArgumentTypeError(
        'Expected a non-empty filepath',
        'filepath',
        'string'
      );
    }
    const serializedOptions = BufferedWorkerPool.serializeOptions(options);
    const result = await this._pool.exec('run', [filepath, serializedOptions]);
    return deserialize(result);
  }
Adds a test file run to the worker pool queue for execution by a worker process.

Handles serialization/deserialization.

@param {string} filepath - Filepath of test
@param {Options} [options] - Options for Mocha instance
@private
@returns {Promise<SerializedWorkerResult>}