typed_key

A SmolStr is a string type that has the following properties

• size_of::<SmolStr>() == size_of::<String>()
• Strings up to 22 bytes long do not use heap allocations
• Runs of \n and space symbols (typical whitespace pattern of indentation in programming laguages) do not use heap allocations
• Clone is O(1)

Unlike String, however, SmolStr is immutable. The primary use-case for SmolStr is a good enough default storage for tokens of typical programming languages. A specialized interner might be a better solution for some use-cases.

Intenrally, SmolStr is roughly an enum { Heap<Arc<str>>, Inline([u8; 22]) }.