I would suggest that you make it configurable if digest (md5 checksum) should be computed and checked, or not, when data is downloaded. Currently it always is, which can lead to performance issues in some cases. Ideally, user should be able to configure when and when not this happens (default should be that it does check).

I am not sure if checksum is also checked when loading from a cached file. I would hope that yes, and that it should also be configured if that happens.

The idea here is that if you are loading same data again and again in a tight loop, you might want to check checksum only the first time, but not every time.