Package githubapi implements notifications.Service using GitHub API client.
NewService creates a GitHub-backed notifications.Service using given GitHub clients. At this time it infers the current user from the client (its authentication info), and cannot be used to serve multiple users.
Caching can't be used for Activity.ListNotifications until GitHub API fixes the odd behavior of returning 304 even when some notifications get marked as read. Otherwise read notifications remain forever (until a new notification comes in). That's why we need clientNoCache.