Function mem::copy_at

pub fn copy_at<T: MemoryBlock>(
    src: &T, 
    dst: &mut T, 
    from: Addr, 
    to: Addr, 
    pos: Addr
) -> Result<Addr, Error>

Copy the contents of src at from to to to dst, starting at pos. Returns Ok(writtenbytes) to signify writtenbytes bytes have been copied, or Err(error) if some error happened during copying.