#3152 allowed calling NpgsqlDataReader.GetStream on any data type; this allows e.g. getting a raw string representation for decoding outside of Npgsql, for efficient JSON decoding.

We could allow the same for NpgsqlDataReader.GetFieldValue<byte[]> and NpgsqlDataReader.GetBytes(), which could be useful in certain short value scenarios. We should probably wait to see if someone cares first.