Is there any way we can send back errors with custom protocols?
E.g. when i access a file that doesn exists with the file:// protocoll, chrome does know the file does not exist (in the devConsole this is logged as net::ERR_FILE_NOT_FOUND)
With my custom foobar:// protocoll, i want to look up files, but trigger errors when specific (e.g. forbidden) files are accessed.

The only current way i can think of is redirecting the call to a file that does not exist for sure:

return new protocol.RequestFileJob('#');

but a specifically triggered error (event with "Forbiden" or "Access Denied" messages) would be much nicer.

I guess it shouldn't be hard to implement, as error feedback already exists here.