[ABAP] OData: $inlinecount implementieren

* https://blogs.sap.com/2017/12/06/display-countfilterorderbyinlinecounttop-and-skip-operations-using-odata-services/
* $inlinecount=allpages
* $inlinecount=none

METHOD xyz_get_entityset.
  
  ...

  IF abap_true = io_tech_request_context->has_inlinecount( ).
    es_response_context-inlinecount = lines( et_entityset ).
  ELSE.
    CLEAR: es_response_context-inlinecount.
  ENDIF.

ENDMETHOD.