docs: function signals() {
  
    /**
     *  Signal handler.
     */
    function interrupt(signal) {
      this.log.notice('received %s, scheduling shutdown', signal);
      this.shutdown(0, process.exit);
    }
  
    interrupt = interrupt.bind(this);
  
    function iterate(signal) {
  
      /* test environment listener leak */
      if(process.listeners(signal).length) return;
  
      process.once(signal, function() {
        interrupt(signal);
      })
    }
  
    ['SIGINT', 'SIGTERM'].forEach(iterate.bind(this));
  }