static double stefansChat_onLine_safetyDelay = 1; // seconds
static double stefansChat_onLine_shortSafetyDelay = 0.1;
static double stefansChat_onLine_errorDelay = 10;
static int stefansChat_onLine_lookback = 0;
static int stefansChat_onLine_firstRead = -1;

static new ThreadLocal<Map> stefansChat_onLine_fullParams;
static new ThreadLocal stefansChat_onLine_onHistoryRead;

static void stefansChat_onLine(int lookback, O f) {
  stefansChat_onLine_lookback = lookback;
  stefansChat_onLine(f);
}

static void stefansChat_onLine(fO f) {
  fO hr = getAndClearThreadLocal(stefansChat_onLine_onHistoryRead);
  thread "Stefan's Chat" {
    int a = stefansChat_onLine_firstRead = max(0, stefansChat_n()-stefansChat_onLine_lookback);
    bool first = true;
    while licensed { pcall {
      S s = loadPageWithTimeout("http://botcompany.de/1008998/raw/incremental?json=1&a=" + a, 120*1000);
      if (empty(trim(s))) {
        sleepSeconds(stefansChat_onLine_safetyDelay);
        //print("Re-polling.");
        continue;
      }
      try {
        Map map = safeUnstructMap(s);
        int n = getInt n(map);
        L msgs = cast get(map, 'msgs);
        for (O msg : msgs)
          try {
            stefansChat_onLine_fullParams.set(mapPlus((Map) msg, chatName := "Stefan's Chat"));
            pcallF(f, getString(msg, 'text));
          } finally {
            stefansChat_onLine_fullParams.set(null);
          }
        sleepSeconds(stefansChat_onLine_shortSafetyDelay);
        a = n;
      } catch e {
        printException(e);
        sleepSeconds(stefansChat_onLine_errorDelay);
      }
      
      if (first) {
        pcallF(hr);
        first = false;
      }
    }} // end pcall, while licensed
  }
}

Began life as a copy of #1009191