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This is a quick fix to help users who are stuck on the "pull" step at
99%.

In the near future we're introducing a new registry client that
should/will hopefully be smarter. In the meantime, this should unblock
the users hitting issue #1736.

A few obvious levels were adjusted, but generally everything mapped to "info" level.

if a download part is inactive for some time, restart it

If the chunk download is interrupted, resume from where we left off

glob returns files in lexical order which is not appropriate when
rebuilding the parts list