An immutable singly linked list that uses the Scala List class
as backing store, but is Java-friendly.
Construct an empty List
Append an item to this list.
Append an item to this list. An O(n) operation where n is the
number of items in the underlying List.
Does the List contain the element
Is the List Empty
Prepends an item to this list.
Prepends an item to this list. O(1)
The size of the List
(Since version 2.8.0) use productIterator instead