/// <summary>
/// Get one of each repeated element.
/// </summary>
public static IDistinctEnumerable <T> GetDistinctRepeatedElements <T>(this IEnumerable <T> enumerable, IEqualityComparer <T> equalityComparer)
{
return(enumerable
.GetRepeatedElements(equalityComparer)
.ToDistinct(equalityComparer)); // No repeats among the non-distinct elements.
}