class_docstr: Class for sending callbacks to DagProcessor using pipe.
  
  It is used when DagProcessor is not executed in standalone mode.
class_docstr_tok: ["Class","for","sending","callbacks","to","DagProcessor","using","pipe",".","It","is","used","when","DagProcessor","is","not","executed","in","standalone","mode","."]
docstr: Send information about the callback to be executed by Pipe.
  
  :param callback: Callback request to be executed.
docstr_tok: ["Send","information","about","the","callback","to","be","executed","by","Pipe",".",":","param","callback",":","Callback","request","to","be","executed","."]
code: def send(self, callback: CallbackRequest):
      """
      Send information about the callback to be executed by Pipe.
  
      :param callback: Callback request to be executed.
      """
      try:
          self._get_sink_pipe().send(callback)
      except ConnectionError:
          # If this died cos of an error then we will noticed and restarted
          # when harvest_serialized_dags calls _heartbeat_manager.
          pass
  
imports: from __future__ import annotations
  from typing import TYPE_CHECKING, Callable
  from airflow.callbacks.base_callback_sink import BaseCallbackSink
label_desc: Use image node_id 2 for calling the PipeCallbackSink obj's underlying member method code with example usage: obj.send(callback) without return types