Wormhole4j v0.3.0: Supports Multi-threaded Concurrency

Introduction Wormhole4j is a Java implementation of the Wormhole index, an ordered in-memory data structure from the EuroSys '19 paper, "Wormhole: A Fast Ordered Index for In-memory Data." By using the strengths of hash tables, prefix trees, and B+ trees, it achieves a worst-case lookup complexity of O(log L) , where L is the length of the key. This makes it very fast for both point lookups and range scans. While earlier versions of the library were fast, they only worked in single-threaded envi