[FEATURE] Asynchronous Search

[Frobeniusnorm]

Is your feature request related to a problem?

OpenSearch allows asynchronous search https://opensearch.org/docs/latest/search-plugins/async/index/, but i couldn't find equivalent functions in the Java API. Scroll is usefull, but if one needs to query for large amounts of data with e.g. collapse async requests are required.

What solution would you like?

Additionally to search a async_search function for the OpenSearchClient.

[dblock]

@Frobeniusnorm want to give the implementation a shot?

[Frobeniusnorm]

@dblock i have never worked with the implementation of opensearch before and honestly don't plan to, but thank you for the offer.