WIP Adds session id to REPL history (#44681)

[bdc34]

This adds a session UUID to the repl history.

#44681

[giordano]

Maybe could use uuid4() instead of UUID(rand(UInt128))?

[StefanKarpinski]

I'm not entirely sure about this. I think I'd prefer to have an option to shard the history file by process, which would also help with situations where the ~/.julia directory is on a shared file system. In other words, instead of saving a UUID with each entry, have separate history files based on host name and PID.

[jariji]

PIDs aren't guaranteed to be unique even within an OS boot, nor across boots.

Process IDs, in the first place, are usually allocated on a sequential basis, beginning at 0 and rising to a maximum value which varies from system to system. Once this limit is reached, allocation restarts at 300 and again increases. In macOS and HP-UX, allocation restarts at 100.

https://en.wikipedia.org/wiki/Process_identifier

Why is uuid not suitable for shared filesystems?