The transaction id is a randomly generated number used to link stun requests and responses (https://tools.ietf.org/html/rfc5389#section-6). Logging this will help us debug ICE network issues. Bug: webrtc:9972 Change-Id: I93167cb119aad99156e8727b6e4eeeff5198f924 Reviewed-on: https://webrtc-review.googlesource.com/c/109720 Commit-Queue: Zach Stein <zstein@webrtc.org> Reviewed-by: Qingsi Wang <qingsi@webrtc.org> Reviewed-by: Elad Alon <eladalon@webrtc.org> Reviewed-by: Björn Terelius <terelius@webrtc.org> Cr-Commit-Position: refs/heads/master@{#25848}