Unencoded CadcTapClient csv response format causes TypeError in astropy Table.read

[SharonGoliath]

When using the results of tap query in 'csv' format to build an astropy Table instance, get a "TypeError: read() should return bytes" exception.

The following code will raise the exception:

subject = net.Subject(certificate='./cadcproxy.pem')
tap_client = CadcTapClient(subject, resource_id='ivo://cadc.nrc.ca/ad')
buffer = io.StringIO()
tap_client.query(query, output_file=buffer, data_only=True,
                             response_format=‘csv’)
table = astropy.table.Table.read(buffer, format='csv')

This can be worked around by using BytesIO(buffer.getvalue().encode('utf-8')) as the argument to Table, but it's inefficient to decode/encode large results sets.