private void leaveGroup(long time) {
   if (Timing.isEnabled() && currentGroup != null) {
     Timing.stop(requestTimer, time);
     requestTimer = null;
     currentGroup = null;
     Timing.exitScope();
   }
 }
 private void enterGroup(String group, long time) {
   if (Timing.isEnabled()) {
     Timing.enterScope();
     requestTimer = Timing.startRequest(GWT_PREFIX + group);
     requestTimer.start(time);
     currentGroup = group;
   }
 }