write after end

I took a quick look at the implementation and it looks like all `Stream#write()` calls are used as if they were synchronous, but [they are not](https://nodejs.org/dist/latest-v8.x/docs/api/stream.html#stream_writable_write_chunk_encoding_callback).

The result is that we close the stream before all writes are done.

Am I correct? Or there is something that I am missing?