code: def test_readinto_read_speed(self):
      tst = np.empty(test_size, np.uint8)
      with open(test_fn, "rb") as f:
          with Timing(
              "copy in ", lambda et_ns: f" {test_size/et_ns:.2f} GB/s"
          ):
              f.readinto(tst)
  
imports: import pathlib, unittest
  import numpy
  from tinygrad import Tensor, Device, dtypes
  from tinygrad.nn.state import safe_load, safe_save, get_state_dict, torch_load
  from tinygrad.helpers import Timing, CI, fetch, temp
label_desc: Use image node_id 1 for calling the TestRawDiskBuffer obj's underlying member method code with example usage: obj.test_readinto_read_speed() without return types