[PATCH] cache: flush stdio before restoring FDs

[Jason A. Donenfeld]

Hey John,

Wow, that was quick. Konstantin and I were just talking about this.
I'll review this and merge things asap.

Another related thing were were discussing and I was just
investigating is the inherent buffering that our cache system uses.
When it's filling a slot, everything is buffered until the end, when
the slot is printed. This doesn't work well for huge tars, which might
buffer for more than an HTTP timeout. I'm looking into calling fork()
before slot->fn() and then calling splice in the parent...

Jason