Race condition causes static file uploads to fail with an HTTP adapter

[gbrail]

A race condition causes file uploads using the "express.static()" middleware to fail for large-ish files when an HTTP adapter is used.

The root cause seems to be one of those wonderful issues where one of the many modules that make up connect (in this case it is called "on-finished" is introspecting on the HTTP request and response objects and looking for various fields such as "finished") is assuming that it is using regular Node code.

The solution is to make our HTTP adapter have more of those special internal fields.