BloomFilterCore (nuget): A Bloom Filter is a probabalistic data structure that Implements the Add() and Contains() methods in a memory efficient manner when compared to the more traditional Hash Set. However, the Bloom Filter has some draw backs:  It will sometimes indicate that an element is in the set when it isn't. The False Positive rate can be decreased by using more memory.  The capacity of the Bloom Filter is fixed at creation time. (You can add more elements than the target capacity, but the False Positive rate continues to increase thereafter).
Keywords: bloom-filter|bloomfilter|bloom