How HighLevelRestClient use complex-DSL?

When I am trying to use DSL in HighLevelRestClient, I found there is no way to build a SearhSourceBuilder.

Then I tried
DyWrapperQueryBuilder wqb = new DyWrapperQueryBuilder(dsl);
I found that only simple DSL like
{"term" : { "user.id" : "kimchy" }} can bu used.

But like
{"from":0,"size":0,"_source":{"includes":["COUNT"],"excludes":[]},"aggregations":{"COUNT(*)":{"value_count":{"field":"_index"}}}}

is always return error msg like this
{"error":{"root_cause":[{"type":"parsing_exception","reason":"[from] query malformed, no start_object after query name","line":2,"col":11}],"type":"parsing_exception","reason":"[from] query malformed, no start_object after query name","line":2,"col":11},"status":400}

I check my DSL is OK. So How can I use DSL like that in HighLevelRestClient ?

Thanks very much !