Hopscotch map

Differences from std::unordered_map, such as iterator invalidation on insert and the need to use it.value() to modify values, can break existing code expecting standard behavior, as admitted in the README.

Requires move-only types to have a nothrow move constructor, which may not always be feasible, limiting usability with certain custom types, as noted in the differences section.

Lacks support for bucket-related methods like bucket_size and bucket, which are available in std::unordered_map and might be needed for specific debugging or optimization tasks.

Multiple classes with different growth policies and security features can confuse users, requiring careful consideration to choose the right one, as indicated in the benchmark advice.