Multiple stream example needs clarify

[baggio002]

When use 1 stream following this example

python-bigquery-storage/samples/to_dataframe/main_test.py

Lines 130 to 139 in 6254bf2

	# This example reads from only a single stream. Read from multiple streams
	# to fetch data faster. Note that the session may not contain any streams
	# if there are no rows to read.
	stream = read_session.streams[0]
	reader = bqstorageclient.read_rows(stream.name)
	# Parse all Arrow blocks and create a dataframe. This call requires a
	# session, because the session contains the schema for the row blocks.
	dataframe = reader.to_dataframe(read_session)
	print(dataframe.head())

, the example perhaps make confusion.

The example states that we can read from multiple streams in order to get data faster. It does not say that multiple streams may be generated automatically if there is a lot of data and so you need to get data from all streams.

Thanks!

[tswast]

Thanks for the report. Yes, we can improve these comments.

Note: I did recently change this sample to request a maximum of 1 stream so that the sample does not miss rows that have been assigned to other streams. #114

[meredithslota]

Converting this to a feature request for a code sample handling multiple streams, as the original issue has been fixed as per Tim. Thanks!