code: def test_metadata(self):
      metadata = {"hello": "world"}
      safe_save({}, temp("metadata.safetensors"), metadata)
      import struct
  
      with open(temp("metadata.safetensors"), "rb") as f:
          dat = f.read()
      sz = struct.unpack(">Q", dat[0:8])[0]
      import json
  
      assert (
          json.loads(dat[8 : 8 + sz])["__metadata__"]["hello"]
          == "world"
      )
  
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 5 for calling the TestSafetensors obj's underlying member method code with example usage: obj.test_metadata() without return types