docs: protected void save(final String fileName, final SessionListener callback) {
          Thread t = new Thread(new Runnable() {
              @Override
              public void run() {
                  Exception thrownException = null;
                  try {
                      save(fileName);
                  } catch (Exception e) {
                  	// ZAP: Log exceptions
                  	log.warn(e.getMessage(), e);
                      thrownException = e;
                  }
                  if (callback != null) {
                      callback.sessionSaved(thrownException);
                  }
              }
          });
          t.setPriority(Thread.NORM_PRIORITY-2);
          t.start();
      }