code: function _activateJob(job) {
      var l = _sortedByPriorityJobs.length;
  
      // Add the job to the running jobs:
      _runningJobs[job.id] = job;
      job.status = 'running';
  
      // Add the job to the priorities:
      if (l) {
        job.weightTime = _sortedByPriorityJobs[l - 1].weightTime;
        job.currentTime = job.weightTime * (job.weight || 1);
      }
  
      // Initialize the job and dispatch:
      job.startTime = __dateNow();
      _dispatch('jobStarted', __clone(job));
  
      _sortedByPriorityJobs.push(job);
    }
docs: Activates a job, by adding it to the _runningJobs object and the
  _sortedByPriorityJobs array. It also initializes its currentTime value.
  
  @param  {Object} job The job to activate.