async Task buildTestAsync(Filter <string> bf)
        {
            var len   = 20;
            var array = new string[len];

            for (int i = 0; i < len; i++)
            {
                array[i] = Utilitiy.GenerateString(10);
            }

            Assert.All(await bf.AddAsync(array), r => Assert.True(r));
            Assert.All(await bf.ContainsAsync(array), r => Assert.True(r));

            Assert.True(await bf.AllAsync(array));

            await bf.ClearAsync();

            Assert.All(await bf.ContainsAsync(array), r => Assert.False(r));
            Assert.False(await bf.AllAsync(array));
        }
 public Task AddAsync()
 {
     return(filter.AddAsync(data));
 }