I've added a new file caching test to test file cachine with multiple
hosts being served. This test should fail right now because we know
that we track only port number but not host name. It doesn't, however,
and the reason is quite simple: StaticResourcesAdapter doesn't use the
file cache code at all. The only "caching" it does is it stores a File
reference to show that it's been validated as an actual file on the
disk. But each request reads it from disk again and again. I'd like to
fix this to actually use the file cache. This should improve
performance, of course, as well as allow me to isolate the bug with
regard to multi-host caching. Any objections?