As Stream */

inequality operator (needed for range-based for)

! @brief compare two value_t enum values @since version 3.0.0 */

post-increment (it++)

subtract from iterator

post-decrement (it--)

! @brief dereference the iterator @pre The iterator is initialized; i.e. `m_object != nullptr`. */

! @brief comparison: less than or equal @pre The iterator is initialized; i.e. `m_object != nullptr`. */

@brief comparison: 3-way @sa https://json.nlohmann.me/api/basic_json/operator_spaceship/

equality operator (needed for InputIterator)

! @brief comparison: greater than @pre The iterator is initialized; i.e. `m_object != nullptr`. */

! @brief comparison: greater than or equal @pre The iterator is initialized; i.e. `m_object != nullptr`. */

! @brief access to successor @pre The iterator is initialized; i.e. `m_object != nullptr`. */

Explicit constructors instead of `using Container::Container` otherwise older compilers choke on it (GCC <= 5.5, xcode <= 9.4)