Reports that a new subscription request has been received and wait for a decision.
public delegate void OnNewSubscriptionRequestedDelegate(Core core, Friend linphoneFriend, string url);
The LinphoneFriend aimed by the subscription.
URI of the subscriber
Note : A subscription request is notified by this function only if the LinphoneSubscribePolicy for the given LinphoneFriend has been set to LinphoneSPWait. See linphone_friend_set_inc_subscribe_policy.