This is a low-level helper for automatically authenticating a request with an OAuth flow, caching the access token and refreshing it where possible. You should only need to use this function if you're implementing your own OAuth flow.
req_oauth(req, flow, flow_params, cache)An oauth_token.
A httr2 request object.
An oauth_flow_ function used to generate the access token.
Parameters for the flow. This should be a named list
whose names match the argument names of flow.
An object that controls how the token is cached. This should be a list containing three functions:
get() retrieves the token from the cache, returning NULL if not
cached yet.
set() saves the token to the cache.
clear() removes the token from the cache