When developing with WDF, how can you send manually created requests to the down-level devices of the current device like WDM?

Question

The current is like this, I implemented an upper-layer filtering driver, I want to create a Write request in the driver and send the request to the next layer of the current device, I refer to the "toaster" example, create WDFIOTARGET, and successfully open, although the request is also sent successfully, but I found that it is actually sent to the driver first, and then to the next layer of the device, that is, not directly to the device I expect, I also tried to use WdfDeviceGetIoTarget to get the target, but the target does not have a file object, so I can't find the relevant information now, I don't know how to proceed to the next step, I hope to get an answer.