I want to add two Vectors which will give me another vector as a result without mutation of the existing ones:
I found a related question, but it does mutate the first one, which I don't want.
Best way to concatenate vectors in Rust
let vec1: Vec<i32> = vec![1, 2, 3];
let vec2: Vec<i32> = vec![4, 5, 6];
let vec3: Vec<i32> = ??; // expected vector equal to vec![1, 2, 3, 4, 5, 6];