class_docstr: Stores data in temp buckets, restitute it shuffled.
code: def _add_to_mem_buffer(self, hkey, data):
      self._mem_buffer.append((hkey, data))
      if self._total_bytes > MAX_MEM_BUFFER_SIZE:
          for hkey, data in self._mem_buffer:
              self._add_to_bucket(hkey, data)
          self._mem_buffer = None
          self._in_memory = False
  
imports: import math
  import os
  import struct
  from typing import Iterator, List, Optional
  import uuid
  from absl import logging
  import six
  from tensorflow_datasets.core import hashing
  from tensorflow_datasets.core.utils import file_utils
  from tensorflow_datasets.core.utils import type_utils
  from tensorflow_datasets.core.utils.lazy_imports_utils import tensorflow
label_desc: Use image node_id 5 for calling the Shuffler obj's underlying member method code with example usage: obj._add_to_mem_buffer(hkey, data) without return types