rafa/docs/Stream-done.md

Rafa.js is a Javascript framework for building concurrent applications.

Return a new child stream that handles all done values that pass 
through the stream. Return values from the handler function have to affect
on values sent to child streams (cannot be transformed).

<aside>
```js
// # each(unit: A => undefined): Stream
var stream = Rafa.stream();
var value = null;

stream.done(v => value = v);

stream.write(23, true); // true = isDone

// value: 23;
```
</aside>