port:
                      description: The port associated with the listener.
                      properties:
                        name:
                          description: Label assigned to the port.
                          type: string
                        number:
                          description: A valid non-negative integer port number.

                    port:
                      description: The port associated with the listener.
                      properties:
                        name:
                          description: Label assigned to the port.
                          type: string
                        number:
                          description: A valid non-negative integer port number.

        requires all optimizer variables to be created at the first
        `apply_gradients()` or `minimize()` call. If your workflow calls
        optimizer to update different parts of model in multiple stages,
        please call `optimizer.build(model.trainable_variables)` before the
        training loop.
    *   **Performance regression on `ParameterServerStrategy`.** This could be