docs: function _createConsumerMessage(consumer, message, {chanId}) {
    const {
      iterator: consumerIterator,
      type: requestType,
      payload
    } = consumer
    if (requestType === cSelectRequest) {
      const {selectedChanIds} = payload
      const i = selectedChanIds.indexOf(chanId)
      const response = new Array(selectedChanIds.length)
      response[i] = message
      return [consumerIterator, response]
    } else if (requestType === cTakeRequest) {
      return [consumerIterator, message]
    }
    throw new Error(`Unknown request type ${requestType}`)
  }