Idea: `final class Teds\ComparableObject {public readonly $key: mixed; public $value; }`

[TysonAndre]

• This could throw for keys that don't have a stable comparison order, e.g. most objects
• stable_compare could check for instances of this class
• This could be used in StableMinHeap, stable sorts, etc.
• This class would override the regular object comparison handler to compare $key if the instances were the same to be usable in <=>, <, sort, etc.