This member is an explicit interface member implementation. It can be used only when the SortedSet<T> instance is cast to an ICollection<T> interface.
A collection that is read-only does not allow the addition, removal, or modification of elements after the collection is created.
A collection that is read-only is simply a collection with a wrapper that prevents modifying the collection; therefore, if changes are made to the underlying collection, the read-only collection reflects those changes.
Getting the value of this property is an O(1) operation.