How can I convert a haxe.Int64 to a Float?

I've got something like

```
var x = haxe.Int64.parseString("1000000000000");

```

and I'd like to convert that to a Float. I've looked in [the Int64 api docs](https://api.haxe.org/haxe/Int64.html), have found `fromFloat`, `ofInt`, and `toInt`, but there's no `toFloat` method in there.