public async Task ArrayPoolUsedByDefault()
        {
            WriteByteArray(20);
            var reader = new StreamPipeReader(Stream);
            var result = await reader.ReadAsync();

            SequenceMarshal.TryGetReadOnlySequenceSegment(
                result.Buffer,
                out var startSegment,
                out var startIndex,
                out var endSegment,
                out var endIndex);

            var start = (BufferSegment)startSegment;
            var end   = (BufferSegment)endSegment;

            Assert.Same(start, end);
            Assert.IsType <byte[]>(start.MemoryOwner);

            reader.AdvanceTo(result.Buffer.End);
            reader.Complete();
        }