docs: public Conditionals ifUnModifiedSince(LocalDateTime time) {
          Preconditions.checkArgument(noneMatch.isEmpty(), String.format(ERROR_MESSAGE, HeaderConstants.IF_UNMODIFIED_SINCE, HeaderConstants.IF_NONE_MATCH));
          Preconditions.checkArgument(!modifiedSince.isPresent(), String.format(ERROR_MESSAGE, HeaderConstants.IF_UNMODIFIED_SINCE, HeaderConstants.IF_MODIFIED_SINCE));
          time = time.withNano(0);
          return new Conditionals(match, empty(), Optional.empty(), Optional.of(time));
      }