code: def test_rewrite_prefetch(self):
      with test_util.deterministic_ops():
          v = variables.Variable(-1, dtype=dtypes.int64)
  
          def map_fn(x):
              v.assign(x)
              return x
  
          dataset = dataset_ops.Dataset.range(5)
          dataset = dataset.map(map_fn)
          dataset = dataset.prefetch(5)
          self.evaluate(variables.global_variables_initializer())
          get_next = self.getNext(dataset, requires_initialization=True)
          self.assertEqual(self.evaluate(v), -1)
          self.assertEqual(self.evaluate(get_next()), 0)
          time.sleep(0.01)
          self.assertEqual(self.evaluate(v), 0)
          self.assertEqual(self.evaluate(get_next()), 1)
          time.sleep(0.01)
          self.assertEqual(self.evaluate(v), 1)
  
imports: import os
  import time
  from absl.testing import parameterized
  import numpy
  from tensorflow.python.compat import v2_compat
  from tensorflow.python.data.experimental.ops import batching
  from tensorflow.python.data.experimental.ops import interleave_ops
  from tensorflow.python.data.experimental.ops import testing
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import options
  from tensorflow.python.data.ops import readers
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import config
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import random_seed
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import cond
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import random_ops
  from tensorflow.python.ops import script_ops
  from tensorflow.python.ops import string_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import test
label_desc: Use image node_id 12 for calling the MakeDeterministicTest obj's underlying member method code with example usage: obj.test_rewrite_prefetch() and returns: x