This provides the TFF orchestration logic connecting the common server logic
which applies aggregated model deltas to the server model with a
ClientDeltaFn that specifies how weight_deltas are computed on device.
A no-arg function that returns a tf.Optimizer. The
apply_gradients method of this optimizer is used to apply client updates
to the server model.
broadcast_process
A tff.templates.MeasuredProcess that broadcasts the
model weights on the server to the clients. It must support the signature
(input_values@SERVER -> output_values@CLIENT).
aggregation_process
A tff.templates.MeasuredProcess that aggregates the
model updates on the clients back to the server. It must support the
signature ({input_values}@CLIENTS-> output_values@SERVER). Must be
None if model_update_aggregation_factory is not None.