Accept any sequence of header pairs, not just list

[gyanu2507]

We only iterate header pairs. Typing them as list meant a tuple or h11.Headers needed a pointless list(...) copy.

Fixes #173

[Kriechi]

I believe this is already deprecated since Python 3.9 - please use collections to import the related types. See https://docs.python.org/3/library/typing.html#deprecation-timeline-of-major-features.

[gyanu2507]

Agreed — typing.Sequence is the deprecated alias. Head uses from collections.abc import Sequence now, and the handshake still materializes list(headers) before handing them to h11, so we are not asking h11 to take an arbitrary sequence.

[gyanu2507]

@Kriechi switched the alias to collections.abc.Sequence in 3330d6d.

[gyanu2507]

@Kriechi switched the alias to collections.abc.Sequence in 3330d6d. Please re-review when you can.

[gyanu2507]

CI is green on tests; the remaining mark is codecov/project coverage. No functional failure on the Sequence-of-headers change.

[gyanu2507]

Pushed Sequence-backed header tests (tuple as well as list) for the list(headers) conversions. GitHub Actions is waiting on maintainer approval for the new run (action_required on the latest CI workflow). Once that runs, Codecov should refresh.