stream with multiple input

Hi,
I have multiple input to xml. When I close on of the input stream, closing other has no effect. I dont get the closing tag for the last element

``` javascript
kml = xml.element({ _attr: { xmlns: 'http://www.opengis.net/kml/2.2'} });
doc = xml.element({})

stream = xml([{kml: kml}, {Document: doc}], {declaration: true})

stream.on 'data', (chunk) ->
console.log(chunk);

doc.close()
kml.close()
```

And here is the output

``` xml

```

Closign tag for kml is missing