/// <summary>
/// Removes all elements in the specified collection from the current set.
/// </summary>
/// <param name="other">The collection of items to remove from the set.</param>
public void ExceptWith(IEnumerable <T> other)
{
var result = ImmutableHashSet <T> .Except(other, this.equalityComparer, this.root);
this.Apply(result);
}