In addition to the delayed ACKs extension, implement the new [ACK Frequency extension](https://datatracker.ietf.org/doc/html/draft-ietf-quic-ack-frequency). Reuse code if possible. Deprecate Delayed ACKs extension in the future (not part of this issue).
In addition to the delayed ACKs extension, implement the new ACK Frequency extension.
Reuse code if possible.
Deprecate Delayed ACKs extension in the future (not part of this issue).