Part of the Event implementation described in RFC3265.
/// <summary> /// Initializes a new instance of the <see cref="SubscriptionState"/> class. /// </summary> /// <param name="state">State to copy.</param> private SubscriptionState(SubscriptionState state) { if (state == null) throw new ArgumentNullException("state"); Expires = state.Expires; Reason = state.Reason; RetryAfter = state.RetryAfter; State = state.State; }