This fails to address the main concern I run into in practice: can you recover if some resources timed out while downloading? This often fails in all sorts of

This fails to address the main concern I run into in practice: can you recover if some resources timed out while downloading? This often fails in all sorts of ways: * The client treats timeout as end-of-file, and thinks the resource is complete even though it isn't. This can be very difficult for the user to fix, except as a side-effect of other breakages. * The client correctly detects the truncation, but either it or the server are incapable of range-based downloads and try to download the whole thing from scratch, which is likely to eventually fail again unless you're really lucky. * Various problems with automatic refreshing. * The client's only (working) option is "full page refresh", and that re-fetches all resources including those that should have been cached. * There's some kind of evil proxy returning completely bogus content. Thankfully less common on the client end in a modern HTTPS world, but there are several ways this can still happen in various contexts.