Happy Wednesday everyone!
I have a piece about HashMaps in the works, but am currently attempting to unravel the entry API, so it might be awhile yet before that piece gets published.
In the meantime, I read this great piece, currated by the "This Week in Rust" folks, regarding the use of preludes and globs.
TLDR: Don't. The author considers them an anti-pattern.
I tend to not use preludes myself. I like to pull in only what I need AND it helps me to understand specifically what I'm using from the library.
Enjoy!