[UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "The members of ObservableCollection<> class were explicitly annotated so this method can use them safely.")]
protected bool SourceIsObservableCollection { get; }

<UnconditionalSuppressMessage("Trimming", "IL2026", Justification:="The members of ObservableCollection<> class were explicitly annotated so this method can use them safely.")>
Protected ReadOnly Property SourceIsObservableCollection As Boolean