Node js WritableStream


### event
- drain
- finish
- error
- close
- pipe
- unpipe


- `writableObjectMode` - 객체를 받기 위해
```typeconst { Writable } = require("stream")const outStream = new Writable({  write(chunk, encodeing, callback) {    console.log(chunk.toString())    callback()  },})process.stdin.pipe(outStream)```
same with
```typeprocess.stdin.pipe(process.stdout)```








