def deliverBody(protocol):
        """
        Register an L{IProtocol<twisted.internet.interfaces.IProtocol>} provider
        to receive the response body.

        The protocol will be connected to a transport which provides
        L{IPushProducer}.  The protocol's C{connectionLost} method will be
        called with:

            - ResponseDone, which indicates that all bytes from the response
              have been successfully delivered.

            - PotentialDataLoss, which indicates that it cannot be determined
              if the entire response body has been delivered.  This only occurs
              when making requests to HTTP servers which do not set
              I{Content-Length} or a I{Transfer-Encoding} in the response.

            - ResponseFailed, which indicates that some bytes from the response
              were lost.  The C{reasons} attribute of the exception may provide
              more specific indications as to why.
        """

        Register an L{IProtocol<twisted.internet.interfaces.IProtocol>} provider
        to receive the response body.

        The protocol will be connected to a transport which provides
        L{IPushProducer}.  The protocol's C{connectionLost} method will be
        called with:

            - ResponseDone, which indicates that all bytes from the response
              have been successfully delivered.

            - PotentialDataLoss, which indicates that it cannot be determined
              if the entire response body has been delivered.  This only occurs
              when making requests to HTTP servers which do not set
              I{Content-Length} or a I{Transfer-Encoding} in the response.

            - ResponseFailed, which indicates that some bytes from the response
              were lost.  The C{reasons} attribute of the exception may provide
              more specific indications as to why.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/iweb.py