elixir-mint / mint / 70b522ee80a69f3c44f899b6c807b89a3ad75b16-PR-481

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main: 88%

Pull #481

github

Track advertised receive window synchronously in initiate/5

Streams opened before the server's SETTINGS ACK arrived were reading
their initial receive window from `conn.client_settings`, which still
held library defaults at that point. If the user advertised a stream
window smaller than the default (e.g. `initial_window_size: 65_535`),
the stream struct tracked the 4 MB default locally while the server
respected the 65_535 we sent in SETTINGS. The client's remaining
window never dropped to the refill threshold, stream-level
WINDOW_UPDATE frames never fired, and the connection stalled once the
server exhausted its per-stream send window.

Mirror the advertised `client_settings_params` into
`conn.client_settings` during `initiate/5` — the sender already knows
what it committed to and doesn't need to wait for the ACK to act on
it. Add a regression test that opens a stream before the ACK round
trip and asserts the stream struct reflects the advertised value.

Also rename `receive_window` to `receive_window_remaining` so the
peak/remaining distinction is clear at the call site, and document
that `:receive_window_update_threshold` is shared between the
connection and per-stream windows (so windows at or below the
threshold refill on every DATA frame).

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