non-blocking function call

gistfile1.js

  backendEvents.once('process_metrics', function (){
    pm.process_metrics(metrics_hash, flushInterval, time_stamp, function emitFlush() {

    // Flush metrics to each backend.
    backendEvents.emit('flush', time_stamp, metrics_hash);

    });
  });
  backendEvents.emit('process_metrics', time_stamp, metrics_hash);