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