code: function startRequest(queueName) {
    // Update queue tracking information
    var info = queueInfo[queueName];
    var time = performance.now() / 1000;
    if (info.timeFirst) {
      info.timeFirst = time;
      info.timeLast  = time;
    } else
      info.timeLast  = time;
    info.requestCount++;
    // Update concurrent request counts
    concurrentPerQueue[queueName] += 1;
    concurrentRequests++;
    // set flag
    queuesChanged = true;
    // Start request
    var queue = queues[queueName];
    var request = queue.shift();
    request.start();
  }
docs: private methods