code: function start(callback) {
  
    let {arc} = readArc()
    let close = x=> !x
  
    // if .arc has events and we're not clobbering with ARC_LOCAL flag
    if (arc.events || arc.queues) {
      // start a little web server
      let server = http.createServer(function listener(req, res) {
        let body = ''
        req.on('data', chunk => {
          body += chunk.toString()
        })
        req.on('end', () => {
          let message = JSON.parse(body)
          if (req.url === '/queues') {
            message.arcType = 'queue'
          } else if (req.url === '/events' || req.url === '/') {
            message.arcType = 'event'
          } else {
            res.statusCode = 404
            res.end('not found')
            console.log(chalk.red.dim('event bus 404 for URL ' + req.url))
            return
          }
          console.log(chalk.grey.dim('@' + message.arcType), chalk.green.dim(JSON.stringify(JSON.parse(body), null, 2)))
          // spawn a fork of the node process
          let subprocess = fork(path.join(__dirname, '_subprocess.js'))
          subprocess.send(message)
          subprocess.on('message', function _message(msg) {
            console.log(chalk.grey.dim(msg.text))
          })
          res.statusCode = 200
          res.end('ok')
        })
      })
      // ends our little web server
      close = function _closer() {
        try {
          server.close()
        }
        catch(e) {
          console.log('swallowing server.close error in sandbox events', e)
        }
      }
      // start listening on 3334
      server.listen(3334, callback ? callback: x=>!x)
    }
    else {
      callback()
    }
    return {close}
  }
docs: creates a little web server that listens for events on 3334