Nutshell of this comes down to that I can't seem to figure out exactly how to get the server to not block the main thread, and to respond to everything in parallel. Do this:
Terminal #1
cargo run --bin server
Terminal #2
cargo run --bin client
And you should see that the server is processing each item sequentially,
blocking the entire thread on the line thread::sleep_ms(1000) on every
iteration. Resource Monitor (on Windows) is definitely spinning up the
correct number of threads. Help?