[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.

[OData] Übersicht zu OData-Abfrageoptionen (Query-Optionen)

Option       | manuell implementieren
-------------+-----------------------
$count       | nein
$expand      | nein
$filter      | ja
$format      | nein
$inlinecount | ja
$link        | nein
$orderby     | ja
$select      | nein
$skip        | ja
$skiptoken   | ja
$top         | ja
$value       | nein

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