class_docstr: Keeps track of strings to add to string_table in pprof proto.
docstr: Gets index that would be assigned to the next added string.
  
  Returns:
    Index of the next string if it was added.
docstr_tok: ["Gets","index","that","would","be","assigned","to","the","next","added","string",".","Returns",":","Index","of","the","next","string","if","it","was","added","."]
code: def next_index(self):
      """Gets index that would be assigned to the next added string.
  
      Returns:
        Index of the next string if it was added.
      """
      return len(self._string_table)
  
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 3 for calling the StringTable obj's underlying member method code with example usage: obj.next_index() and returns: len