code: def initialize(self, dask_server=None, extra=None):
      self.server = dask_server
      self.extra = extra or {}
      self.plugin = WebsocketPlugin(self, self.server)
      self.server.add_plugin(self.plugin)
  
imports: from __future__ import annotations
  import json
  import logging
  import os
  import os.path
  from datetime import datetime
  from typing import TYPE_CHECKING, Any
  from tlz import first, merge
  from tornado import escape
  from tornado.websocket import WebSocketHandler
  from dask.typing import Key
  from dask.utils import format_bytes, format_time
  from distributed.diagnostics.websocket import WebsocketPlugin
  from distributed.http.utils import RequestHandler, redirect
  from distributed.metrics import time
  from distributed.utils import log_errors
label_desc: Use image node_id 1 for calling the EventstreamHandler obj's underlying member method code with example usage: obj.initialize(dask_server, extra) without return types