return getCrawlerDocumentCharsAsArray(CRAWLER_DOCUMENT_SPACE_CHARS, getCrawlerDocumentSpaceChars());
    }

    default String[] getCrawlerDocumentSpaces() {
        String[] spaces = (String[]) propMap.get(CRAWLER_DOCUMENT_SPACES);
        if (spaces == null) {
            spaces = Arrays.stream(getCrawlerDocumentSpaceCharsAsArray()).mapToObj(Character::toString).toArray(n -> new String[n]);

                }
                else if ( last == null ) {
                    // don't have enough credits/space for the first request, block until available
                    // for space there is nothing we can do, callers need to make sure that a single message fits

                    try {
                        long timeout = getResponseTimeout(chain);