It's taken a while for spraying and trimming to go from being a crazy research idea to mainstream in UEC, but if you're interested, the old animations from my Sigcomm 2017 talk still give the general idea: https://www.youtube.com/watch?v=BO0QhaxBRr0
In addition to what is in the video, UEC introduces a new libfabric-based transport layer and a new congestion control scheme. Plus a bunch of stuff at the lower layers like link-layer retransmit. Hopefully the specs will reach 1.0 around the the end of the year - unfortunately at the moment you can only get them if you're a member of UEC.