docs: public void dumpEphemerals(PrintWriter pwriter) {
          Set<Long> keys = ephemerals.keySet();
          pwriter.println("Sessions with Ephemerals ("
                  + keys.size() + "):");
          for (long k : keys) {
              pwriter.print("0x" + Long.toHexString(k));
              pwriter.println(":");
              HashSet<String> tmp = ephemerals.get(k);
              synchronized (tmp) {
                  for (String path : tmp) {
                      pwriter.println("\t" + path);
                  }
              }
          }
      }