public void TestStreamReadWrite()
        {
            var rnd = new Random();

            for (var c = 0; c < count; c++)
            {
                var memSize = rnd.Next(1, 10_000);
                var mem     = new byte[(memSize + 4) * writeRepeatCount];
                var answer  = new byte[memSize * writeRepeatCount];
                rnd.NextBytes(answer);

                for (var bc = 1; bc < writeRepeatCount; bc++)
                {
                    for (var offset = 0; offset < bc; offset++)
                    {
                        var span1 = new MemoryStreamer(mem);
                        var span2 = new MemoryStreamer(mem);

                        span1.Write(answer, offset, bc - offset);
                        var buffer = new byte[bc + offset];
                        span2.Read(buffer, offset, bc - offset);

                        Assert.Equal(new Span <byte>(answer).Slice(offset, bc - offset).ToArray(), new Memory <byte>(buffer).Slice(offset, bc - offset).ToArray());
                    }
                }

                Assert.Throws <ArgumentNullException>(() =>
                {
                    var s = new MemoryStreamer(mem);
                    s.Read(null, 0, 1);
                });
            }
        }