if-modified-since

Hi,

I would like to downsize data that is sent between client and server by using the gateway feature last modified and cache control.

I've added if-modified-since to the header of my odata call in my sapui5 application to retrieve some entityset.

however, when i debug in my data provider, io_tech_request_context->get_if_modified_since( ) doesn't return any value.

What am i missing?

thanks

Peter