virtual bool do_is_equal(const std::pmr::memory_resource& other) const noexcept = 0;
*this for equality with
memory_resources compare equal if and only if memory allocated from one
memory_resource can be deallocated from the other and vice versa.
The most-derived type of
other may not match the most derived type of
*this. A derived class implementation therefore must typically check whether the most derived types of
other match using dynamic_cast, and immediately return
false if the cast fails.
 See also
| compare for equality with another |
(public member function)