code: function cleanWaiters(state)
  {
    var list = state._currentTask.waiters;
  
    Object.keys(list).forEach(function(job)
    {
      // prevent callback from execution
      // by modifying up `once`'s `called` property
      list[job].callback.called = true;
  
      // if called it will return false
      list[job].callback.value = false;
  
      // send termination signal to the job
      list[job].terminator();
  
      // report termination
      report('killed', state, list[job].command);
  
      delete list[job];
    });
  }
docs: Cleans leftover jobs provided by the list
  
  @param   {object} state - current state
  @returns {void}