Attempts to refresh the access token using the refresh token.
Updates both in-memory tokens and the session cookie.
Concurrent callers are automatically deduplicated: if a refresh is already
in progress every additional caller awaits the same promise rather than
issuing a second request that would invalidate the first one.
Attempts to refresh the access token using the refresh token. Updates both in-memory tokens and the session cookie.
Concurrent callers are automatically deduplicated: if a refresh is already in progress every additional caller awaits the same promise rather than issuing a second request that would invalidate the first one.