As a best-selling author, I invite you to explore my books on Amazon . Don't forget to follow me on Medium and show your support. Thank you! Your support means the world! When I first learned to program, I believed that abstraction always came with a cost. If I wrote a function that worked with many types, I had to choose between writing the same code over and over or paying a runtime penalty for polymorphism. Then I encountered Rust’s trait system, and my understanding of that trade‑off vanished. Rust offers a contract: you write generic code once, and the compiler generates specialized, hand‑tuned versions for each concrete type you use. The abstraction is free. There is no hidden tax. Let me show you what I mean with the simplest possible example. Suppose you want to compute the area of different shapes. In many languages you’d write a function that takes an interface or a base class, then dispatch to the right implementation at runtime.…