code: function $$cluster() {
      if (cluster.isMaster) {
          $LogProvider.info(
              `Starting ${cyan('cluster')} on ${os.cpus().length} core(s)`
          );
  
          if (config.development === true) {
              $LogProvider.warn(
                  `It is not recommended to use ${cyan('cluster')} in development`
              );
          }
  
          os.cpus().forEach(cluster.fork);
  
          // We only want to refork if the user has not explicitly set the
          // `--no-refork` option
          if (!argv.hasOwnProperty('norefork')) {
              cluster.on('exit', cluster.fork);
          }
      } else {
          $$server();
      }
  }
docs: @desc $$cluster forks the standard webserver process allowing for many child
  forks of the webserver to spin up. This is based on the native NodeJS cluster
  module, which will spin up a new process for each of the CPUs on the host
  machine.
  
  The master/child for cluster is self-forking by default. This insures that if
  a fork goes down, the master will spin a new child fork up automatically,
  allowing for more application resiliency. This may make it difficult to
  restart the entire process as default shell exit commands will not take down
  all of the forks.
  
  It is not recommended to use cluster in development.
  @todo With binding and sockets, one must make sure that the clustered app
  listens across all of it's listeners and clients broadcast to a broker or
  all of the children
  @since 0.4.5
  @access private