class_docstr: FileWriter for test.
  
  TensorFlow FileWriter uses TensorFlow's Protobuf Python binding
  which is largely discouraged in TensorBoard. We do not want a
  TB.Writer but require one for testing in integrational style
  (writing out event files and use the real event readers).
code: def add_event(self, event):
      if isinstance(event, event_pb2.Event):
          tf_event = tf.compat.v1.Event.FromString(
              event.SerializeToString()
          )
      else:
          tf_event = event
          if not isinstance(event, bytes):
              logger.error(
                  "Added TensorFlow event proto. "
                  "Please prefer TensorBoard copy of the proto"
              )
      super().add_event(tf_event)
  
imports: import threading
  import tensorflow
  from tensorboard.compat.proto import event_pb2
  from tensorboard.compat.proto import graph_pb2
  from tensorboard.compat.proto import meta_graph_pb2
  from tensorboard.compat.proto import summary_pb2
  from tensorboard.util import tb_logging
label_desc: Use image node_id 3 for calling the FileWriter obj's underlying member method code with example usage: obj.add_event(event) without return types