/// <summary>
/// Determines whether the <see cref="ICollection{T}"/> contains a specific value.
/// </summary>
/// <param name="item">The object to locate in the <see cref="ICollection{T}"/>.</param>
/// <returns>
/// true if <paramref name="item"/> is found in the <see cref="ICollection{T}"/>; otherwise, false.
/// </returns>
public bool Contains(T item)
{
return(ImmutableHashSet <T> .Contains(item, this.Origin));
}
public ImmutableHashSet <T> Difference(ImmutableHashSet <T> other)
{
return(ImmutableHashSet.From(this.Where(t => !other.Contains(t))));
}
