A data structure for consistent hashing

Creates a new ConsistentHashing data

new function only takes one initial node at first. This interface is like non-empty list which aims to ensure one node always available at least for distribution.

If you want, you can add some more nodes one by one using add function.

Adds a node

Removes a node

This function actually does not remove all nodes. The node added with new function is irremovable.

Gets one node by key