use processes not threads for workers about aici HOT 2 CLOSED

communication channel:

• shared memory object with 4 semaphores (rd/wr times req/resp) and message size at the beginning
• parent sets it up under random name and passes name to child (keeping the channel open)
• child opens the channel and unlinks it
• child responds to parent that it's ready
• can probably serialize/deserialize JSON directly from memory (later)

other:

• make sure we put children in the same process group (?) so that a SIGTERM kills them all
• have a service for caching of WASM images and compilation; talk to it via REST? or also message channel
• use the new message channel also for Python?
• don't compile and run the WASM in the same process to limit fork() time (amount of mem to copy or sth)
• probably exec() for first child, only fork() for actual forks in search
• unmap parent's comms channel in child when forked; madvice() unmap on fork or sth
• time (external) and memory (kernel) limits on children
• every ~1ms sem_trywait() - both for step() and async stuff

from aici.

Windows doesn't have POSIX SHM; macOS doesn't have sem_init(); maybe we should just use TCP sockets for interprocess comms

from aici.