When taking apart the iPad Pro, iFixit discovered a Fresco Logic FL1100 4-port USB 3.0 Host Controller, pointing towards support for USB 3.0 transfer speeds. Support for USB 3.0 speeds is notable because the Lightning port on current iPads and iPhones can only transfer data at around 25 to 35MB/s, which is USB 2.0 speed. At USB 3.0 speeds, data transfers would be upwards of 60MB/s and up to 625MB/s.
USB 3.0-style speeds for data transfers over Lightning have been rumoured to be coming to Apple devices for several years now, but have thus far not materialized.
Several reports have pointed to the upcoming release of new adapters that will enable the faster file transfers, but the release timeline is not clear yet. It is also not known if Apple plans on introducing new Lightning cables that will enable USB 3.0 speeds when transferring files from a computer to an iPad Pro.