static S renderSleepingThreadsWithStackTraces() {
  Map<Thread, StackTraceElement[]> threadMap = Thread.getAllStackTraces();
  S threadDescription = "sleeping thread";
  new StringBuilder buf;
  int n = 0;
  for (Thread t : threadMap.keySet()) {
    continue if isThreadRunnable_x(t, threadMap.get(t));
    ++n;
    printTo(buf, t);
    for (StackTraceElement e : threadMap.get(t)) {
      printTo(buf, "  " + e);
    }
    printTo(buf);
  }
  printTo(buf, n(n, threadDescription) + ".");
  ret asciiHeading2(n(n, threadDescription) + " (+" + (l(threadMap)-n)  + ")") + "\n" + buf;
}