code: func MapBufferRange(target uint32, offset int, length int, access uint32) unsafe.Pointer {
  	ret, _, _ := syscall.Syscall6(gpMapBufferRange, 4, uintptr(target), uintptr(offset), uintptr(length), uintptr(access), 0, 0)
  	return (unsafe.Pointer)(ret)
  }
docs: // map all or part of a buffer object's data store into the client's address space