code: function createOperationDescriptor(
    request: ConcreteRequest,
    variables: Variables,
  ): OperationDescriptor {
    const operation = request.operation;
    const operationVariables = getOperationVariables(operation, variables);
    const dataID = ROOT_ID;
    return {
      fragment: {
        dataID,
        node: request.fragment,
        variables: operationVariables,
      },
      node: request,
      root: {
        dataID,
        node: operation,
        variables: operationVariables,
      },
      variables: operationVariables,
    };
  }
docs: Creates an instance of the `OperationDescriptor` type defined in
  `RelayStoreTypes` given an operation and some variables. The input variables
  are filtered to exclude variables that do not match defined arguments on the
  operation, and default values are populated for null values.