code: @Override
    public Tuple getNext() throws IOException {
      if (tupleTemplate == null) {
        tupleTemplate = new ProjectedProtobufTupleFactory<M>(typeRef, requiredFieldList);
      }
  
      M value = getNextBinaryValue(typeRef);
      return value != null ?
          tupleTemplate.newTuple(value) : null;
    }
docs: Return every non-null line as a single-element tuple to Pig.
  <p>
  A small fraction of bad records in input are tolerated.
  See  {@link LzoRecordReader} for more information on error handling.