code: function getUid(username, options) {
    const uid = _.tryOnce(findUser(username, options), 'id');
    return _.isUndefined(uid) ? null : uid;
  }
docs: Get user UID
  @function $os~getUid
  @param {string} username
  @param {Object} [options]
  @param {boolean} [options.refresh=true] - Setting this to false allows operating over a cached database of users,
  for improved performance. It may result in incorrect results if the affected user changes
  @param {boolean} [options.throwIfNotFound=true] - By default, this function throws
  an error if the specified user cannot be found
  @returns {number|null} - The user ID or null, if it cannot be found
  @example
  // Get UID of user 'mysql'
  $os.getUid('mysql');
  // => 1001