Rust development builds became unbearably slow. Then I found a way to get ~1 second rebuilds!

I really like Rust, and I'm honestly in love with it. I never thought I'd go back to Go, especially considering some of its significant shortcomings for me: undefined nil, lack of proper enums and match, no Result or Option, etc. But over the last few weeks, as my projects have grown significantly, I've started seeing development build times (edit → save → run) of 30–50 seconds, even after trying every remedy (for example, everything listed here). I can't wait that long. I need to use Windows...