I can write to stream which is ended.

Should I be able to write to the stream which has ended?
If I do:

```
var one = H([1, 2, 3]);
one.consume(function (err, x, push, next) {
if (x === H.nil) {
console.log('Nil')
} else {
console.log(x);
}
next();
}).each(H.log);
one.write(4); //throw expected here, but it does not happen.
//Output is: [1, 2, 3, Nil, 4]
```

Start by running the reproduction using H([1, 2, 3]), consume, and write(4), and observe the output after H.nil. Trace the stream lifecycle around consume, the ended state, and write to determine the intended behavior. Done means the behavior of writing after the stream ends is defined and covered by an appropriate test.

Written by the indexing model from the issue text.