Add progress to streaming download (#1268)

Add progress to streaming download (#1268)

* Added last_raw_chunk_size to the Response object (#1208)

* Added example with progress bar (#1208)

Co-authored-by: Florimond Manca <florimond.manca@gmail.com>
* Apply suggestions from code review

Co-authored-by: Florimond Manca <florimond.manca@gmail.com>
* PR review
Changed last_raw_chunk_size to num_bytes_downloaded ;
Edited the example according to documentaion

* Update docs/advanced.md

Co-authored-by: Florimond Manca <florimond.manca@gmail.com>
* Update docs/advanced.md

Co-authored-by: Florimond Manca <florimond.manca@gmail.com>
* Update docs/advanced.md

* Update docs/advanced.md

Co-authored-by: Florimond Manca <florimond.manca@gmail.com>
Co-authored-by: Tom Christie <tom@tomchristie.com>