private Optional<String> getRequestHeader(final HttpServletRequest request, final CIKey header) {
        if (header == null) {
            return Optional.empty();
        }
        final String value = request.getHeader(header.get());
        return Optional.ofNullable(value)
                .filter(NullSafe::isNonBlankString);
    }
@return An optional containing a non-blank attribute value, else empty.
stroom-receive/stroom-receive-common/src/main/java/stroom/receive/common/DataFeedKeyServiceImpl.java