Bug: Async SequentialStream reads do not complete

[Wraith2]

Based on the binary read benchmark in #593 (comment) I tried the code below expecting the behaviour to be fast and found that it simply blocks indefinitely.

            using var conn = new SqlConnection(ConnectionString);
            using var cmd = new SqlCommand("SELECT foo FROM data", conn);
            await conn.OpenAsync();
            using var reader = await cmd.ExecuteReaderAsync(
                System.Data.CommandBehavior.SequentialAccess
            );
            await reader.ReadAsync();
            using var stream =  reader.GetStream(0);
            using var memory = new MemoryStream(16 * 1024);

            await stream.CopyToAsync(memory);
            return (int)memory.Length;

This should work but freezes in a task wait after a single read cycle, the second read never completed. If you change it to standard mode it'll work but it does so by fetching the entire field and giving you a reader over the byte[]. So no workaround, this needs fixing if the team agree that it's a bug.

Edit: for clarity the problem is when multiple packets are needed. The current tests read from a single packet and thus do not do a network read.

[cheenamalhotra]

Thanks @Wraith2

Ack. Yes that does seem like an issue, if you have a proposed fix, let us know if you'd like to create PR, or we will start working on it soon.

[cheenamalhotra]

Adding note: This issue is not reproducible in NetFx driver (for .NET Framework) so it should be investigated since when this issue has started to occur for .NET Core applications.