* Popen cleanup.
* Improve the test for response headers.
* Fix default headers of Httpx and H2 handlers, add tests.
* Check Location in redirect tests.
* Simplify bindaddress tests.
* Add download_latency to HttpxDownloadHandler, add tests.
* Remove explicit method="GET".
* Don't expect a specific value in test_download_with_maxsize_very_large_file
* Use a non-existent scheme in test_unsupported_scheme.
* Remporarily rollback the test_download_latency test check.
* Better check in test_download_latency.
* Improve logic for StreamCloseReason.CANCELLED.
Andrey Rakhmatullin
Julian Hamze