/// <summary>
/// Gets the multiple CLR resource identifiers for the given CLR resource type.
/// </summary>
/// <remarks>
/// The CLR based resource identifiers can come from either json:api resource objects or
/// resource identifiers.
/// </remarks>
/// <typeparam name="TResource">Type of CLR resource to find.</typeparam>
/// <typeparam name="TResourceId">Type of CLR resource identifier.</typeparam>
/// <returns>Returns the LINQ-to-objects collection of CLR resource identifiers if they exist,
/// empty collection otherwise.</returns>
public static IEnumerable <TResourceId> GetResourceIdCollection <TResource, TResourceId>(this IDocumentReader documentReader)
where TResource : class, IResource
{
Contract.Requires(documentReader != null);
var clrResourceType = typeof(TResource);
var clrResourceIdCollection = documentReader.GetResourceIdCollection <TResourceId>(clrResourceType);
return(clrResourceIdCollection);
}