class_docstr: Start a new data server as a subprocess.
class_docstr_tok: ["Start","a","new","data","server","as","a","subprocess","."]
code: def data_provider(self):
      if self._data_provider is None:
          raise RuntimeError("Must call `start` first")
      return self._data_provider
  
imports: import errno
  import logging
  import os
  import subprocess
  import tempfile
  import time
  import grpc
  import pkg_resources
  from tensorboard.data import grpc_provider
  from tensorboard.data import ingester
  from tensorboard.data.proto import data_provider_pb2
  from tensorboard.util import tb_logging
label_desc: Use image node_id 2 for calling the SubprocessServerDataIngester obj's underlying member method code with example usage: obj.data_provider() and returns: self