I'm having a real hard time getting acngfs to work reliably, and it
starts straining my good will quite a bit.  The impression that I'm
getting is that it finishes system calls before the underlying
download has finished which manifests as hashes being calculated
incorrectly in aptitude/apt-get/apt which makes acngfs useless.

Other behaviour I'm observing: apt-cacher-ng constantly terminates
not-yet-finished downloads only to retry them anew quickly after which
results in a lot of wasted bandwidth and incomplete files under
/var/cache/apt-cacher-ng/debrep which I then have to delete manually
because for some reason apt-cacher-ng does not detect the corruption
itself.  I have observed the behaviour only when accessing files
through acngfs.  Downloading a file with wget using apt-cacher-ng as
the proxy works fine.

I run acngfs like this:

/usr/lib/apt-cacher-ng/acngfs http://deb.debian.org/debian \
    /var/local/acngfs_debian proxy=127.0.0.1:3142 \
    cachedir=/var/cache/apt-cacher-ng/debrep \
    -o allow_root,auto_unmount,intr,intr_signal=10 -f -d

I took squid out of the picture, so I don't think it has anything to
do with this.

That's all I have.  I wish I could offer more details, but the
software is nigh undebuggable and its architecture completely
incomprehensible to me.