Function enum_underlying

modules/3rd_party/magic_enum/magic_enum.hpp:1189–1191

// Returns underlying value from enum value.
template <typename E>
[[nodiscard]] constexpr auto enum_underlying(E value) noexcept -> detail::enable_if_t<E, underlying_type_t<E>> {
  return static_cast<underlying_type_t<E>>(value);
}

// Obtains index in enum values from enum value.
// Returns optional with index.