It should be possible to provide Bulk Action on Connection and Engine.

$engine->bulk(string $index, \Generator $saveDocuments, \Generator $deleteDocuments, bulkSize: 100);

// and

$indexer->bulk(Index $index, \Generator $saveDocuments, \Generator $deleteDocuments, bulkSize: 100);

Engine not supporting bulk action can fallback to basic save and delete methods.

The documents should be able to be aryor \Generator for performance.

A BulkableIndexerInterface should be added so the fallback to the save/delete can be part of the Engine and not every adapter itself need to implement it.

Bulk Action make maybe sense in case of:

Implementing of Reindex Providers #16