Threaded Red Black Tree in C#

A Threaded Red Black Tree in C# (cand be used both like a SortedSet and LinkedList)
Implementing TopDown Deletion and TopDown Insertion mainly from http://eternallyconfuzzled.com with few personal flavours
Time Complexity for inserting and deleting N nodes is O(NlogN) (both are 0-10% faster than SortedSet )
Time Complexity for Exist, Find, MoveNext is O(logN)
Time complexity for Traversing N nodes is O(N) ( 30-40% faster than SortedSet because of using tree threads)
Traversing in sorted order doesnt use a stack, so you can start traversing from any node
Nodes are public and can use them to move tru collection line in a LinkedList (moving takes O(1) for half of nodes and O(logN) in worst case)
Modifying the Tree doesnt invalidate the iterators