Using Rayon for Simple Parallelization of SQL Queries in Rust

When building a Rust API backend, running two independent SQL queries sequentially caused noticeable UI lag. The solution was using rayon::join to run both queries in parallel with minimal boilerplate. Unlike parallel iterators, rayon::join accepts two closures of different types and handles thread management and synchronization transparently, resulting in clean, safe concurrent code without manual channel setup or thread joining.