private static void AuthorChanged(BindableObject bindable, object oldValue, object newValue)
{
RadChat chat = (RadChat)bindable;
AuthorsMap authors = GetAuthorsMap(chat);
chat.Author = authors.GetOrCreateAuthor((ChatroomParticipant)newValue);
}
public static void SetAuthorsMap(BindableObject bindable, AuthorsMap value)
{
bindable.SetValue(AuthorsMapProperty, value);
}