45     return <type-identifier>;
    57 template<
typename T, 
int TypeId>
 
static constexpr int getTypeId() noexcept
provides a tag type for simple types 
static constexpr int getTypeId() noexcept
constexpr SimpleTag(const T &value) noexcept
explicitly convertible from T 
Base class for packet tags that can hold any arbitrary information.