[BUG] Search Request preference cannot be set to _primary

[ravi4theja]

What is the bug?

Supplying _primary to search request builder's preference is throwing illegal argument exception.

How can one reproduce the bug?

Create a search request using SearchRequest.Builder and set the preference option to _primary

What is the expected behavior?

It should take in the _primary as a preference according to open search docs

What is your host/environment?

MacOS Sonoma 14.2.1

Do you have any screenshots?

Do you have any additional context?

I was wondering is there are any enums I can use instead of passing in a _primary string to the search request preference.

[dblock]

Is this a server-side error?