Method reserve

include/boost/json/string.hpp:1064–1070

Increase the capacity to at least a certain amount. This increases the capacity of the array to a value that is greater than or equal to `new_capacity`. If `new_capacity > `@ref capacity(), new memory is allocated. Otherwise, the call has no effect. The number of elements and therefore the @ref size() of the container is not changed. If new memory

        @throw boost::system::system_error `new_capacity > `@ref max_size().
    */
    void
    reserve(std::size_t new_capacity)
    {
        if(new_capacity <= capacity())
            return;
        reserve_impl(new_capacity);
    }

    /** Request the removal of unused capacity.