Configuration struct containing JSON API information for a request
Much of the data in this struct is populated for you by various Plugs this library offers if you choose to use them.
includes_post_processor, if nil, will default to running all includes
through Enum.uniq/1. You can customize this behavior if needed with a
function that accepts two arguments: The includes about to be seriailzed and
the requested includes for the current request. Your function must return the
includes as you want them to be serialized.