docs: function streamRecorder () {
    let lastKey, lastStream
    return (key, createStream) => {
      if (isFunction(key)) key = key.call()
  
      debug(`Recorder get key: ${key}`)
  
      if (key !== lastKey) {
        debug(`Recorder will return a new stream`)
  
        lastKey = key
        lastStream = createStream.call(null, key)
      }
  
      return lastStream
    }
  }