Update io_uring

[tkp1n]

following the updates to kernel v5.6.

https://github.com/torvalds/linux/blob/v5.6/include/uapi/linux/io_uring.h

@tmds I marked this as a draft, because I need your input regarding the best handling of zero-length array in the struct io_uring_probe: https://github.com/torvalds/linux/blob/7111951b8d4973bda27ff663f2cf18b663d15b48/include/uapi/linux/io_uring.h#L243

[tkp1n]

@tmds Could I please get your feedback on this? I'd love to start experimenting with the more recent io_uring functions...

[tmds]

zero-length array in the struct io_uring_probe

I add a static get method that is named after the field.
for example, C:

           struct file_handle {
               unsigned int  handle_bytes;   /* Size of f_handle [in, out] */
               int           handle_type;    /* Handle type [out] */
               unsigned char f_handle[0];    /* File identifier (sized by
                                                caller) [out] */
           };

cs:

    public unsafe struct file_handle
    {
        public uint handle_bytes;
        public int handle_type;

        public static byte* f_handle(file_handle* fh)
            => (byte*)(fh + 1);
    }

[tkp1n]

@tmds Thanks for your feedback! Should be ready to merge now... PTAL

[tmds]

Thank you for the update!