code: func memoryMapFile(file *os.File, write bool) (mmap.MMap, []uint32, error) {
  	// Try to memory map the file
  	flag := mmap.RDONLY
  	if write {
  		flag = mmap.RDWR
  	}
  	mem, err := mmap.Map(file, flag, 0)
  	if err != nil {
  		return nil, nil, err
  	}
  	// Yay, we managed to memory map the file, here be dragons
  	header := *(*reflect.SliceHeader)(unsafe.Pointer(&mem))
  	header.Len /= 4
  	header.Cap /= 4
  
  	return mem, *(*[]uint32)(unsafe.Pointer(&header)), nil
  }
docs: // memoryMapFile tries to memory map an already opened file descriptor.