feature request: `spi-watch`, show me bytes being sent/recieved.

[mjsir911]

Hi!

Appreciate the project a lot.

I'm trying to reverse engineer an spi driver and it would be super helpful to have some sort of "monitor the spi bytes being sent/recieved on a bus".

Let me know if there's any interest in this or if there are other projects better suited for this that you know of.

Thanks!