code: function jobCallback(job, worker, index) {
  
          if (index < ALEXA_SIZE) {
              var line = lines[index].trim();
  
              var split = line.split(',');
              var id = parseInt(split[0]);
              var url = split[1];
              job({
                  id : id,
                  url : url
              }, function(err) {
                  // Lets log if it worked
                  total++;
                  if (err) {
                      console.log('Problem  #' + worker.id + ': ' + err.message + ' for line: ' + line);
                  } else {
                      console.log('    #' + worker.id + '  DONE: ' + line);
                      successful++;
                  }
                  if (total % 10 === 0) {
                      console.log('################## ' + successful + '/' + total + ' (success/crawled) ################################');
                  }
              });
          } else {
              // no more content!
              job(null);
          }
      }
docs: Called when a worker is ready for a new job job is the function that needs to be called to execute the job index contains a number (starting at 0) that is increased with each jobCallback call