Using py4j to send a large dataset to the jvm is really slow, so we use either a file
        or a socket if we have encryption enabled.
        :param data:
        :param serializer:
        :param reader_func:  A function which takes a filename and reads in the data in the jvm and
                returns a JavaRDD. Only used when encryption is disabled.
        :param createRDDServer:  A function which creates a PythonRDDServer in the jvm to
               accept the serialized data, for use when encryption is enabled.
        :return:

def _serialize_to_jvm(self, data, serializer, reader_func, createRDDServer):
        """
        Using py4j to send a large dataset to the jvm is really slow, so we use either a file
        or a socket if we have encryption enabled.
        :param data:
        :param serializer:
        :param reader_func:  A function which takes a filename and reads in the data in the jvm and
                returns a JavaRDD. Only used when encryption is disabled.
        :param createRDDServer:  A function which creates a PythonRDDServer in the jvm to
               accept the serialized data, for use when encryption is enabled.
        :return:
        """
        if self._encryption_enabled:
            # with encryption, we open a server in java and send the data directly
            server = createRDDServer()
            (sock_file, _) = local_connect_and_auth(server.port(), server.secret())
            chunked_out = ChunkedStream(sock_file, 8192)
            serializer.dump_stream(data, chunked_out)
            chunked_out.close()
            # this call will block until the server has read all the data and processed it (or
            # throws an exception)
            r = server.getResult()
            return r
        else:
            # without encryption, we serialize to a file, and we read the file in java and
            # parallelize from there.
            tempFile = NamedTemporaryFile(delete=False, dir=self._temp_dir)
            try:
                try:
                    serializer.dump_stream(data, tempFile)
                finally:
                    tempFile.close()
                return reader_func(tempFile.name)
            finally:
                # we eagerily reads the file so we can delete right after.
                os.unlink(tempFile.name)