I'm really happy to see the FUSE passthrough support merged! I have a use case for which it'd be nice to start FUSE passthrough some time after the initial open: I have a network-backed filesystem, and in some cases I'd like to serve an initial request before retrieving the full file. For instance, for a library .so file, I'd love to service the initial 832-byte read while still downloading the full file. Would it be possible to add support for transitioning an open FUSE file to being backed by passthrough *after* the initial open? Could that work with the current passthrough architecture? (I realize that this might be more complex, as the initial open is a good time to directly substitute a file from the underlying filesystem.) Thanks, Josh Triplett
