code: function isLockHolder(task, requestorId) {
    if(!task.semaphore) {
      throw new LockError('TaskNotLocked');
    }
    var requestKey  = hashKey(requestorId, task.id);
  
    return requestKey === task.semaphore.key;
  }
docs: Does the given ID refer to the current lock holder?
  ---------------------------------------------------
  @param {Task} task
  @param {string} requestorId
  @return {bool}
  @throws {LockError}
  @api {public}