Add Optional ECN MetaData to Addressed Envelope (#1502)
Add Optional ECN MetaData to Addressed Envelope (#1502)

Add Optional ECN MetaData to Addressed Envelope

Motivation:

This is a very small step along the path to #1472

Modifications:

Add an optional metadata field to addressed envelope. Currently the only possible data is ECN information. This is not currently populated anywhere.

Result:

Metadata in place for future work.

Co-authored-by: Cory Benfield <e2b4f0650e369574e9b0029c3b3893634b6d4097@apple.com>
apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio