Error message for missing keyfile is hard to interpret #7
Description
If I start Delve with the Undo backend but no keyfile, debugging fails as follows:
$ dlv --backend=undo debug hello
live-record: Maximum event log size is 256M
Hello, world!
live-record: Saving to '/tmp/undo000042204'...
live-record: Termination recording written to /tmp/undo000042204
undodb-5.3.0 (build 423f4a8294cfa8b124916e5efd1b852f7deee8fe) undodb-server
using inferred keyfile: /home/grees/core/release-local/key
Listening on port 43301
Connection established
could not launch process: protocol error E03 during registers read for packet $g
It would be very hard for a user to deduce from this message that the problem is that the inferred keyfile does not exist.