docs: static <T extends FieldMetadata> Function<T, Optional<Boolean>> getThriftFieldIsLegacyId()
      {
          return new Function<T, Optional<Boolean>>()
          {
              @Override
              public Optional<Boolean> apply(@Nullable T input)
              {
                  if (input == null) {
                      return Optional.absent();
                  }
                  Boolean value = input.isLegacyId();
  
                  if (input.getId() == null || input.getId().shortValue() == Short.MIN_VALUE) {
                      if (value != null && value.booleanValue() == false) {
                          return Optional.absent();
                      }
                  }
  
                  return Optional.fromNullable(value);
              }
          };
      }