Add #derive[clone] to framebuffer struct

[UlmerMan]

I added derive(Clone) to some structs, as i need this for my current project. Because I need to have the raw data and not a reference, as i want to pass it on to a different thread.

[chemicstry]

Adding clone on MemoryMappedFrameBuffer might be okay, but I need to verify this. Cloning FrameBuffer on the other hand, is not sound, because that would allow simultaneously passing the same buffer to capture pipeline and obtaining &[u8], so data in an immutable slice would be overwrittten.

[fishrockz]

So i have typically had one thread to handle the libcamera interaction and then other threads for other things, this can work ok https://gitlab.com/pointswaves/e-camera/-/blob/willsalmon/pi/hmi-app/src/main.rs?ref_type=heads https://gitlab.com/gorse/pi-camera/-/tree/trying?ref_type=heads both use this and while there very messy they do work.

Its not to say that its the only way to go tho.

Clone is typically a bit of a issue because it allow you to have 2 versions of the same thing, and if libcamera has one pointer and we have two things doing different things to it then we can have issues.

That said we might be able to send structs between threads, I think that is the functionally you really want. Send is a bit trick too but it might be a better way to go but making sure that it is also sound is also a bit tricky.

[UlmerMan]

@fishrockz this is the thing I need but I am not a that good of a rust developer to implement that the best why so I just used clone