class_docstr: A class for visualizing execution timelines of TensorFlow steps.
class_docstr_tok: ["A","class","for","visualizing","execution","timelines","of","TensorFlow","steps","."]
docstr: Allocate a flow Id.
docstr_tok: ["Allocate","a","flow","Id","."]
code: def _alloc_flow_id(self) -> int:
      """Allocate a flow Id."""
      flow_id = self._next_flow_id
      self._next_flow_id += 1
      return flow_id
  
imports: import collections
  import copy
  import json
  import re
  from typing import Any, Dict, List, Optional, Tuple, Union
  from tensorflow.core.framework import step_stats_pb2
  from tensorflow.python.platform import build_info
  from tensorflow.python.platform import tf_logging
label_desc: Use image node_id 3 for calling the Timeline obj's underlying member method code with example usage: obj._alloc_flow_id() and returns: flow_id