class_docstr: Keeps track of strings to add to string_table in pprof proto.
code: def __init__(self):
      # Pprof requires first entry in string_table to be ''.
      self._string_table = [""]
      self._string_to_index = {"": 0}
  
imports: from collections import defaultdict
  from collections import namedtuple
  import gzip
  import os
  import string
  import sys
  import time
  from proto import profile_pb2
label_desc: Use image node_id 1 to create a new StringTable object from inherited base classes: object with example: obj = StringTable()