message: supporting protocol changes
diff: @@ -38,7 +38,7 @@ class DispatcherConfig(
  port: Specifies the port to bind to. A value of 0 indicates that the server
  may bind to any available port.
  protocol: The protocol to use for communicating with the tf.data service.
  - Acceptable values include `"grpc" and "grpc+local"`.
  + Defaults to the only acceptable value of `"grpc"`.
  work_dir: A directory to store dispatcher state in. This
  argument is required for the dispatcher to be able to recover from
  restarts.
  @@ -206,7 +206,7 @@ class WorkerConfig(
  port: Specifies the port to bind to. A value of 0 indicates that the worker
  can bind to any available port.
  protocol: (Optional.) Specifies the protocol to be used by the server.
  - Acceptable values include `"grpc" and "grpc+local"`.
  + Defaults to the only acceptable value of `"grpc"`.
  """
  def __new__(cls,
  