I'm reasonably happy with this one. I'm sure there's an easier way to determine the smallest distance, at least for part 1, but this works fast enough for me.
There is a lot to be disliked here, starting with the Line Length calculation, which I'm sure I'm just totally overthinking or otherwise being dumb about, to the way I'm picking the next point while moving along the line.
Also, TIL how much of a difference a good GetHashCode() override can make when comparing/equating custom struct instances. Not implementing GetHashCode() on this solution resulted in ~250ms runtime on my PC. Implementing a "bad" GetHashCode() (which was `return x.GetHashCode() | y.GetHashCode();` which seemed fine to me ¯\_(ツ)_/¯) resulted in >1s runtime on my PC. Using this implementation (HashCode.Combine()) results in ~25ms runtime on my PC. Those numbers are with nothing changing other than the implementation of GetHashCode() on struct Point.
I also disabled nullability in my quest to improve performance here. The compiler was complaining that my Equals() override wasn't equivalent because of nullability, so it had to be `object? obj` which I didn't care for since this was a value type and not a reference type.
I have no idea what I'm doing in Rust, and I definitely don't understand
borrowing yet, so this is a hideous solution on multiple fronts. I'm not
sure that I'll be sticking with Rust as AoC doesn't feel like a
conducive environment to learn it in.