code: function wrapError(message, cause) {
    var err = new Error(f('%s: %s', message, cause.message));
    err.cause = cause;
    return err;
  }
docs: Wrap something in an error.
  
  @param message {String} The new error's message.
  @param cause {Error} The cause of the error. It is available as `cause`
  field on the outer error.
  
  This is used to keep the argument of emitters' `'error'` event errors.