'Run a request using the specific instance of a transport. Returns the
negotiated protocol string.'

def _negotiatedProtocolForTransportInstance(self, t):

    a = http._genericHTTPChannelProtocolFactory('')
    a.requestFactory = DummyHTTPHandlerProxy
    a.makeConnection(t)
    for byte in iterbytes(self.requests):
        a.dataReceived(byte)
    a.connectionLost(IOError('all    done'))
    return a._negotiatedProtocol
