Note that this has already been fixed: https://bugs.chromium.org/p/webrtc/issues/detail?id=9082

In M66, there was a regression noticed in a sample page that transfers data over a loopback connection: https://webrtc.github.io/samples/src/content/datachannel/datatransfer/

It went from taking 28 seconds to taking 48 seconds. This was due to a usrsctp change that resulted in packets of an unexpected size being generated, logging an error message for every packet sent: https://cs.chromium.org/chromium/src/third_party/webrtc/media/sctp/sctptransport.cc?l=908&rcl=3ef3bfc2aafa707985c9e9dcd4cfb6ccbc525628

This issue would be encountered for any application that uses data channels to send messages larger than the MTU (for example, when transferring a file or some other large piece of data that's chunked up).

Although it's pretty late for M66 changes, this has a very non-risky 1-line fix: https://webrtc-review.googlesource.com/c/src/+/66943

So I'm requesting a merge to M66.