Are you trying to create a driver which limits flow rates or are you trying to create a miniport driver for a particular adapter (hardware) with novel flow control?
These are dramatically different things.
There is no way to ‘tell’ the system to limit itself to a particular send rate. The NIC sends at a rate determined by the medium. The Miniport accepts send NBLs and processes them to completion based on the NIC sending them. Protocols originate send NBLs and give them to the Miniport until they hit their resources limit (whatever that might be).
There is a component which is part of the QoS solution in Windows that schedules (and therefore has a rate limiting effect) on traffic but it is purely software and operates between the TCPIP stack and the NIC as a filter.
Just what exactly are you trying to accomplish?
Good Luck,
Dave Cattley