pipe to writable with parameters

Hey there, first: I absolutely love your work, great library! Makes working with streams so much fun and has great inter-op with ramda!

This is more a question than an issue because I couldn't find a better place to ask it:

Is there a idiomatic way to dynamically create write streams and pipe to them, using some derived file name?

Currently I'm doing something like:

``` javascript
const writeFile = ({filename, content}) =>
fs.createWriteStream(filename).write(content)

stream
.map(writeFile)
.done(/* consumes the stream */)
```

However, I'd prefer to simply consume the write stream via `pipe` like:

``` javascript
stream.pipe(writeFile)
```
What would be a better way to do this?

/edit:
And from the [node docs](https://nodejs.org/api/fs.html#fs_fs_write_fd_buffer_offset_length_position_callback) I can tell my version is not actually safe for writing to the same file in sequence ....

Start by reading Highland's pipe API alongside the Node.js fs.createWriteStream documentation linked in the issue. Compare the requested dynamically named writable streams with the existing stream behavior; completion would require a decided API design and documented expected handling for sequential writes.

Written by the indexing model from the issue text.