Sam Jaffe728fe6d8b9Fix stack overflow in `register_callback` because `lambdas::FFL` would prefer `F &&` where `F` is a `std::function` over `std::function const &`.
728fe6d8b9
Fix stack overflow in `register_callback` because `lambdas::FFL` would prefer `F &&` where `F` is a `std::function` over `std::function const &`.