public static void AddFriend(this Member user, int friendId, Action onSuccess)
{
if (user.Id == friendId)
{
throw new MsgException("You should already be friends with yourself. Otherwise, please contact your local support group.");
}
if (user.IsFriendsWith(friendId))
{
throw new MsgException("You are already friends.");
}
if (FriendshipRequest.Exists(user.Id, friendId))
{
throw new MsgException("You have already sent a request to this user.");
}
FriendshipRequest.Create(user.Id, friendId);
onSuccess();
}