Exchange the value of this object, its comparator functor, its hasher functor, and its maxLoadFactor with those of the specified other object. Additionally, if bslstl::AllocatorTraits<ALLOCATOR>::propagate_on_container_swap is true, then exchange the allocator of this object with that of the other object, and do not modify either allocator otherwise. This method provides the no-throw exception-safety guarantee unless any of the comparator or hasher functors throw when swapped, leaving both objects in a safely destructible, but otherwise unusable, state. The operation guarantees O[1] complexity. The behavior is undefined unless either this object has an allocator that compares equal to the allocator of other, or the trait bslstl::AllocatorTraits<ALLOCATOR>::propagate_on_container_swap is true.