USB 2.0 transmits SOF/uSOF at fixed 1 ms/125 μs intervals. A device driver may change
the interval with small finite adjustments depending on the implementation of host and
system software. USB 3.0 adds mechanism for devices to send a Bus Interval Adjustment
Message that is used by the host to adjust its 125 μs bus interval up to +/-13.333 μs.
In addition, the host may send an Isochronous Timestamp Packet (ITP) within a relaxed
timing window from a bus interval boundary.