Mirror Proxied Downloads
As an enterprise using nuget we need to ensure we always have the bits for every dependency we use. We also want to mitigate risk of a package disappearing from a feed like nuget.org that we don't control.
We would much rather be able to proxy a feed in our myget feed, and have any download proxied packages automatically mirrored. This would help ensure a removed package is still available and potentially help in outage scenarios where the original feed is down.
Would you only auto-mirror packages that have been downloaded at least once or all packages matching the upstream filter?