The introduction documents dedicate many paragraphs to explaining the difference between new() and make(), but in practice, you can create objects within local scope and return them.
Why would you use the pair of allocators?
See Question&Answers more detail:
os 与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
