which implements the handshaking logic of the DTLS-STUN piggybacking.
Not wired up yet, split from
https://webrtc-review.googlesource.com/c/src/+/362480
BUG=webrtc:367395350
Change-Id: I9ee8ff17af4ec96fb891d9852ac50825155735a8
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/370679
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Jonas Oreland <jonaso@webrtc.org>
Reviewed-by: Jonas Oreland <jonaso@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#43606}
f0ca2dc934