bsl::unordered_map::swap

Exchange the value, hasher, key‐equality functor, and max_load_factor of this object with those of the specified other object; also exchange the allocator of this object with that of other if the (template parameter) type ALLOCATOR has the propagate_on_container_swap trait, and do not modify either allocator otherwise. This method provides the no‐throw exception‐safety guarantee if and only if both the (template parameter) types HASH and EQUAL provide no‐throw swap operations; if an exception is thrown, both objects are left in valid but unspecified states. This operation guarantees O[1] complexity. The behavior is undefined unless either this object was created with the same allocator as other or ALLOCATOR has the propagate_on_container_swap trait.