/// <summary>
/// Gets the multiple related CLR resources referenced by the "to-many" relationship.
/// </summary>
/// <typeparam name="TResource">Type of related CLR resource to get.</typeparam>
/// <param name="relationship">The "to-many" relationship object that defines the
/// multiple related CLR resources by json:api resource linkage.</param>
/// <returns>Returns the LINQ-to-objects collection of related CLR resources
/// referenced by the "to-many" relationship if they exist, empty collection otherwise.</returns>
/// <exception cref="DocumentReadException">Is thrown if the relationship object
/// passed is a "to-one" relationship instead of a "to-many" relationship.</exception>
public static IEnumerable <TResource> GetRelatedResourceCollection <TResource>(this IDocumentReader documentReader, Relationship relationship)
where TResource : class, IResource
{
Contract.Requires(documentReader != null);
Contract.Requires(relationship != null);
var clrRelatedResourceType = typeof(TResource);
var clrRelatedResourceCollection = documentReader
.GetRelatedResourceCollection(clrRelatedResourceType, relationship)
.Cast <TResource>();
return(clrRelatedResourceCollection);
}