We've reference for using $apply query option in odata uri at client side(http://docs.oasis-open.org/odata/odata-data-aggregation-ext/v4.0/cs01/odata-data-aggregation-ext-v4.0-cs01.html).
Can anyone please let me know how to use olingo lib for server usage to handle $apply. The link, https://olingo.apache.org/doc/odata4/ only shows about handling other system query options except $apply.