private async Task TestHash(IEnumerable <Func <string, ulong> > hashFuncs)
        {
            var bloom = new MemoryBloomFilter(hashFuncs, 5000000);

            var urls = await File.ReadAllLinesAsync("urls.txt", Encoding.UTF8);

            var duplication = false;


            foreach (var url in urls)
            {
                if (!bloom.TryAdd(url))
                {
                    duplication = true;

                    _output.WriteLine(url);
                }
            }

            Assert.False(duplication);
        }