by read of codesource, the RestApiClientApi just need elasticsearch package for Serialise / deserialize object send and receive by the server..
I wish that would be so easy.
But that requires a lot of work.
If it clashes with what you have, you can use the low level client but you won't have any request builder or response parser.
What you'd like to see is on his way. The team is decoupling more and more the existing code and splitting in modules which would hopefully make that possible at some point.