[Libguestfs] GSoC: Next step nbdcopy (file-ops)

I have been analyzing the code base and I think I should start with nbdcopy file-ops as it's easier to work on. I will try different approaches based on the features provided by liburing. I might need to modify the interfaces `asynch_{read, write}` which is easier in the case of file operations. I will update this thread regarding progress and question. I plan to add iouring_prep_read based functionality till Sunday. Regards, Abhay