FASTEST way to calculate the distance between two points

I’m needing this for a current project, so I have been digging around quite a bit (with little luck) on finding the distance between two points VERY fast. Yes, it is quite critical that it be as optimized as possible.

I have the basics, Pythagorean Theorem run in different ways, as well as the Point.distance() function.

Any more? Any better ways to optimize the Pythagorean Theorem code?