Using the 11” Pro, I can confirm it has capability for 1Gbps via USB-C Ethernet adapter. I tested this today with a Startech US1GC30B USB-C to Ethernet adapter. No additional power needed for this 10/100/1000 adapter, unlike previous iPads. I also have the Belkin USB-C to Ethernet adapter (the one Apple sells on their website) en route, I will test as well. I have 1Gbps service via AT&T Fiber 1000, and my Speedtest app results hover around 750-850Mbps up/down.