Support for multiple using variables

[KathleenDollard]

The following is legal in C#

using (var x as new X(), y as new Y())

which is semantically equivalent to

using (var x as new X())
using (y as new Y())

Kendall Miller and others said "huh that works?"
Other folks using it to simplify things like graphics.

I'd like to support this, but I haven't figured out the best way. The answer may be similar to variables, but the expansion is nested and that is going to be a bit ugly.

No current design.