code: def start(self):
      self.client_stream.on_recv(self.dispatch_submission, copy=False)
      if self.is_leaf:
          super().start()
      else:
          for outgoing_stream in self.outgoing_streams:
              outgoing_stream.on_recv(self.dispatch_result, copy=False)
      self.log.info(f"BroadcastScheduler {self.name} started")
  
file_path: ipyparallel/ipyparallel/controller/broadcast_scheduler.py
imports: import logging
  import zmq
  from traitlets import Bool, Bytes, Integer, List, Unicode
  from ipyparallel import util
  from ipyparallel.controller.scheduler import Scheduler, ZMQStream, get_common_scheduler_streams
label_desc: Use image node_id 1 for calling the BroadcastScheduler obj's underlying member method code with example usage: obj.start() without return types