rocket.chat.mqtt/node_modules/readable-stream/writable.js

It's a MQTT Server, using redis to scale horizontally.

var Stream = require("stream")
var Writable = require("./lib/_stream_writable.js")

if (process.env.READABLE_STREAM === 'disable') {
  module.exports = Stream && Stream.Writable || Writable
} else {
  module.exports = Writable
}