message: Introduce an experimental distributed variable values proto field.
  This is the proto change only. This field will enable the saving of
  information about a distributed variable's underlying variables.
diff: @@ -141,6 +141,13 @@ message SavedVariable {
  VariableAggregation aggregation = 5;
  string name = 6;
  string device = 7;
  + // List of component variables for a distributed variable.
  + //
  + // When this field is non-empty, the SavedVariable will be assumed
  + // to be a distributed variable defined by the components listed here.
  + //
  + // This is only supported by experimental loaders at the moment.
  + repeated SavedVariable experimental_distributed_variable_components = 8;
  }
  