With the introduction of the new multi operations in roaring we need to see what we can optimize;

• Not a big win here, we should ensure roaring optimize well the small iterators. Implemented in meilisearch/milli@4e70d5c. https://github.com/meilisearch/milli/blob/ebddfdb9a329e955066b15ffae17c3a4d496e9c9/milli/src/search/criteria/proximity.rs#L271-L286
• https://github.com/meilisearch/milli/blob/ebddfdb9a329e955066b15ffae17c3a4d496e9c9/milli/src/search/criteria/attribute.rs#L239-L256
• Implemented in meilisearch/milli@632fc3d. https://github.com/meilisearch/milli/blob/ebddfdb9a329e955066b15ffae17c3a4d496e9c9/milli/src/search/criteria/mod.rs#L348-L364
• Implemented in meilisearch/milli@2b70cd0. https://github.com/meilisearch/milli/blob/ebddfdb9a329e955066b15ffae17c3a4d496e9c9/milli/src/search/criteria/mod.rs#L367-L371
• Implemented in meilisearch/milli@9f9feed. https://github.com/meilisearch/milli/blob/ebddfdb9a329e955066b15ffae17c3a4d496e9c9/milli/src/search/criteria/mod.rs#L381-L397
• Implemented in meilisearch/milli@25bd6e7. https://github.com/meilisearch/milli/blob/ebddfdb9a329e955066b15ffae17c3a4d496e9c9/milli/src/update/index_documents/helpers/merge_functions.rs#L35-L77