code: def _abortConnection(self):
          
          transport = self.transport
          if isinstance(transport, TransportProxyProducer):
              transport = transport._producer
  
          if hasattr(transport, 'abortConnection'):
              transport.abortConnection()
          else:
              self.log.error(
                  'Transport {} has no abortConnection method'.format(transport))
docs: We need a way to close the connection when an event line is too long
          or if we time out waiting for an event. This is normally done by
          calling :meth:`~twisted.internet.interfaces.ITransport.loseConnection``
          or :meth:`~twisted.internet.interfaces.ITCPTransport.abortConnection`,
          but newer versions of Twisted make this complicated.
  
          Despite what the documentation says for
          :class:`twisted.internet.protocol.Protocol`, the ``transport``
          attribute is not necessarily a
          :class:`twisted.internet.interfaces.ITransport`. Looking at the
          documentation for :class:`twisted.internet.interfaces.IProtocol`, the
          ``transport`` attribute is actually not defined and neither is the
          type of the ``transport`` parameter to
          :meth:`~twisted.internet.interfaces.IProtocol.makeConnection`.
  
          ``SseProtocol`` will most often be used with HTTP requests initiated
          with :class:`twisted.web.client.Agent` which, in newer versions of
          Twisted, ends up giving us a
          :class:`twisted.web._newclient.TransportProxyProducer` for our
          ``transport``. This is just a
          :class:`twisted.internet.interfaces.IPushProducer` that wraps the
          actual transport. If our transport is one of these, try call
          ``abortConnection()`` on the underlying transport.