message: Add reference to location of API definition
diff: @@ -21,6 +21,8 @@ namespace tensorflow {
  namespace data {
  namespace experimental {
  +// See tensorflow/core/api_def/base_api/api_def_SamplingDataset.pbtxt for the
  +// API definition that corresponds to this kernel.
  class SamplingDatasetOp : public UnaryDatasetOpKernel {
  public:
  // Names of op parameters, public so that they can be accessed by test cases.
  