class_docstr: Abstractly implements the SummaryWriter API.
  
  This API basically implements a number of endpoints (add_summary,
  add_session_log, etc). The endpoints all generate an event protobuf, which is
  passed to the contained event_writer.
code: def _add_event(self, event, step):
      event.wall_time = time.time()
      if step is not None:
          event.step = int(step)
      self.event_writer.add_event(event)
  
imports: import os.path
  import time
  import warnings
  from tensorflow.core.framework import graph_pb2
  from tensorflow.core.framework import summary_pb2
  from tensorflow.core.protobuf import meta_graph_pb2
  from tensorflow.core.util import event_pb2
  from tensorflow.python.eager import context
  from tensorflow.python.framework import meta_graph
  from tensorflow.python.framework import ops
  from tensorflow.python.platform import gfile
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.summary import plugin_asset
  from tensorflow.python.summary.writer.event_file_writer import EventFileWriter
  from tensorflow.python.summary.writer.event_file_writer_v2 import EventFileWriterV2
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 9 for calling the SummaryToEventTransformer obj's underlying member method code with example usage: obj._add_event(event, step) without return types