Matt asked if xz should really be a filter rather than a plugin. The
answer is yes, of course it should be! That's been something in the
todo file for a while.
The commit converts the xz plugin code into a filter (leaving the
plugin around, but deprecating it).
plugin: nbdkit xz file.xz
filter: nbdkit --filter=xz file file.xz
plugin: # can't be done
filter: nbdkit --filter=xz curl
url=https://example.com/disk.xz
This is only lightly tested but it works for local files and for the
curl example given in the commit message. Unfortunately because of
the very large block size used in the Fedora cloud image, the curl
example is barely usable. We should get them to use a more reasonable
block size such as 16M (currently 192M).
Rich.