/// <summary>
/// Observe collection element's IObservable sequence.
/// </summary>
/// <typeparam name="TElement">Collection element type</typeparam>
/// <typeparam name="TProperty">Type of observable property element</typeparam>
/// <param name="source">Source collection</param>
/// <param name="propertySelector">IObservable selection expression</param>
/// <returns>IObservable sequence sequence</returns>
public static IObservable <PropertyPack <TElement, TProperty> > ObserveElementObservableProperty <TElement, TProperty>(this IFilteredReadOnlyObservableCollection <TElement> source, Expression <Func <TElement, IObservable <TProperty> > > propertySelector)
where TElement : class, INotifyPropertyChanged =>
INotifyCollectionChangedExtensions.ObserveElementObservableProperty(source, propertySelector);
/// <summary>
/// Observe collection element's PropertyChanged event.
/// </summary>
/// <typeparam name="TElement">Type of Element</typeparam>
/// <param name="source">source collection</param>
/// <returns>PropertyChanged event stream.</returns>
public static IObservable <SenderEventArgsPair <TElement, PropertyChangedEventArgs> > ObserveElementPropertyChanged <TElement>(this IFilteredReadOnlyObservableCollection <TElement> source)
where TElement : class, INotifyPropertyChanged =>
INotifyCollectionChangedExtensions.ObserveElementPropertyChanged <IFilteredReadOnlyObservableCollection <TElement>, TElement>(source);
/// <summary>
/// Observe collection element's property.
/// </summary>
/// <typeparam name="TElement">Type of element</typeparam>
/// <typeparam name="TProperty">Type of property</typeparam>
/// <param name="source">Data source</param>
/// <param name="propertySelector">Property selection expression</param>
/// <param name="isPushCurrentValueAtFirst">Push current value on first subscribe</param>
/// <returns>Property sequence</returns>
public static IObservable <PropertyPack <TElement, TProperty> > ObserveElementProperty <TElement, TProperty>(this IFilteredReadOnlyObservableCollection <TElement> source, Expression <Func <TElement, TProperty> > propertySelector, bool isPushCurrentValueAtFirst = true)
where TElement : class, INotifyPropertyChanged =>
INotifyCollectionChangedExtensions.ObserveElementProperty(source, propertySelector, isPushCurrentValueAtFirst);
