I think there must be still some corp frameworks that do use it extensively, but it's just not heard all that much about. Some examples, (Broadcom) Vmware NSX-

I think there must be still some corp frameworks that do use it extensively, but it's just not heard all that much about. Some examples, (Broadcom) Vmware NSX-T gateways, Alivaba used to use it, and a lot of extreme HFT use it too, mostly to reduce latency and manipulate tcp.