/// <summary>
/// Creates a process that periodically calls the given session manager's CleanUpOldSessions()
/// method at the specified interval.
/// </summary>
/// <typeparam name="TSession">The type of session used by the given session manager.</typeparam>
/// <param name="sessionManager">The session manager.</param>
/// <param name="interval">The interval at which to schedule clean-ups.</param>
/// <returns>The Timer threading object associated with the periodic clean-up process.</returns>
public static Timer CreateCleanUpTimer <TSession>(this ISessionManager <TSession> sessionManager, TimeSpan interval)
where TSession : ISession
{
if (interval < TimeSpan.Zero)
{
throw new ArgumentOutOfRangeException("interval", "Clean up interval must be positive.");
}
return(new Timer(state => sessionManager.CleanUpOldSessions(), null, interval, interval));
}