template<typename Fn>
slang::function_ref class

An efficient, type-erasing, non-owning reference to a callable.

This is intended for use as the type of a function parameter that is not used after the function in question returns.

This class does not own the callable, so it is not in general safe to store a function_ref.

NOTE: This is based on the type of the same name from the LLVM project.