code: static boolean isFieldRequired(Field field) {
      BigQueryDataField bqAnnotation = field.getAnnotation(BigQueryDataField.class);
  
      return (bqAnnotation != null && bqAnnotation.mode().equals(BigQueryFieldMode.REQUIRED))
          || field.getType().isPrimitive();
    }
docs: Returns true if the field is annotated as a required bigquery field.