message: Add return statement to end of ToVlogString(dnn::DataType data_type)
  Whilst the switch statement covers all possible enum values, the compiler still complains that it reaches the end of the function without returning a value.
  I add an "unknown" string, mirroring the one in the function just above.
diff: @@ -192,6 +192,7 @@ string ToVlogString(dnn::DataType data_type) {
  case dnn::DataType::kInt8:
  return "dnn::DataType::kInt8";
  }
  + return "unknown DataType";
  }
  // Used together with PARAM to VLOG calls made to the stream. Intended
  