text: module.exports = function customStock (options) {
    const processFn = processStream
    return [ options, 'stocks.*', processFn, finishFn ]
  }
  
  function processStream (data, next) {
    return new Promise(function (/* resolve, reject */) {
      setTimeout(function () {
        console.log(data)
        next()
      }, 500)
    })
  }
  
  function finishFn () {
    return console.log('Finished')
  }
  