HashSet<Point> is slower than HashSet<String>

[ericwood8]

Summary
Fix the Point datatype to be one of the generics throughout all generics in C#.

Motivation
GOAL 1- Performance.
GOAL 2- Less code by developer.

Planning:

Point needs to be considered one of the generics. So check not only HashSet but other things you can set to generics.
PointComparer : IEqualityComparer needs a good Equals() and GetHashCode()

Suggested reading:
https://stackoverflow.com/questions/46142734/why-is-hashsetpoint-so-much-slower-than-hashsetstring

[huoyaoyuan]

The stackoverflow post is highly outdated. System.Drawing.Point implemented IEquatable in .NET Core 2.0, which was published at 2017.

[huoyaoyuan]

It's also answered at dotnet/csharplang#8458 with the exact same answer.

[kasperk81]

net framework 4.7 https://dotnetfiddle.net/xu6SYJ 0.96s
net8.0 https://dotnetfiddle.net/dy9R9P 0.03s

that's 32 times faster or 97% improvement!