public void emit() {
      if (mPrevious == null) {
        mPrevious = new AggregatedStats(null, key);
      }

      maybeCount("note_post", (numPostedByApp - mPrevious.numPostedByApp));
      maybeCount("note_update", (numUpdatedByApp - mPrevious.numUpdatedByApp));
      maybeCount("note_remove", (numRemovedByApp - mPrevious.numRemovedByApp));
      maybeCount("note_with_people", (numWithValidPeople - mPrevious.numWithValidPeople));
      maybeCount("note_with_stars", (numWithStaredPeople - mPrevious.numWithStaredPeople));
      maybeCount("people_cache_hit", (numPeopleCacheHit - mPrevious.numPeopleCacheHit));
      maybeCount("people_cache_miss", (numPeopleCacheMiss - mPrevious.numPeopleCacheMiss));
      maybeCount("note_blocked", (numBlocked - mPrevious.numBlocked));
      maybeCount("note_with_actions", (numWithActions - mPrevious.numWithActions));
      maybeCount("note_private", (numPrivate - mPrevious.numPrivate));
      maybeCount("note_secret", (numSecret - mPrevious.numSecret));
      maybeCount("note_prio_max", (numPriorityMax - mPrevious.numPriorityMax));
      maybeCount("note_prio_high", (numPriorityHigh - mPrevious.numPriorityHigh));
      maybeCount("note_prio_low", (numPriorityLow - mPrevious.numPriorityLow));
      maybeCount("note_prio_min", (numPriorityMin - mPrevious.numPriorityMin));
      maybeCount("note_interupt", (numInterrupt - mPrevious.numInterrupt));
      maybeCount("note_big_text", (numWithBigText - mPrevious.numWithBigText));
      maybeCount("note_big_pic", (numWithBigPicture - mPrevious.numWithBigPicture));
      maybeCount("note_fg", (numForegroundService - mPrevious.numForegroundService));
      maybeCount("note_ongoing", (numOngoing - mPrevious.numOngoing));
      maybeCount("note_auto", (numAutoCancel - mPrevious.numAutoCancel));
      maybeCount("note_large_icon", (numWithLargeIcon - mPrevious.numWithLargeIcon));
      maybeCount("note_inbox", (numWithInbox - mPrevious.numWithInbox));
      maybeCount("note_media", (numWithMediaSession - mPrevious.numWithMediaSession));
      maybeCount("note_title", (numWithTitle - mPrevious.numWithTitle));
      maybeCount("note_text", (numWithText - mPrevious.numWithText));
      maybeCount("note_sub_text", (numWithSubText - mPrevious.numWithSubText));
      maybeCount("note_info_text", (numWithInfoText - mPrevious.numWithInfoText));

      mPrevious.numPostedByApp = numPostedByApp;
      mPrevious.numUpdatedByApp = numUpdatedByApp;
      mPrevious.numRemovedByApp = numRemovedByApp;
      mPrevious.numPeopleCacheHit = numPeopleCacheHit;
      mPrevious.numPeopleCacheMiss = numPeopleCacheMiss;
      mPrevious.numWithStaredPeople = numWithStaredPeople;
      mPrevious.numWithValidPeople = numWithValidPeople;
      mPrevious.numBlocked = numBlocked;
      mPrevious.numWithActions = numWithActions;
      mPrevious.numPrivate = numPrivate;
      mPrevious.numSecret = numSecret;
      mPrevious.numPriorityMax = numPriorityMax;
      mPrevious.numPriorityHigh = numPriorityHigh;
      mPrevious.numPriorityLow = numPriorityLow;
      mPrevious.numPriorityMin = numPriorityMin;
      mPrevious.numInterrupt = numInterrupt;
      mPrevious.numWithBigText = numWithBigText;
      mPrevious.numWithBigPicture = numWithBigPicture;
      mPrevious.numForegroundService = numForegroundService;
      mPrevious.numOngoing = numOngoing;
      mPrevious.numAutoCancel = numAutoCancel;
      mPrevious.numWithLargeIcon = numWithLargeIcon;
      mPrevious.numWithInbox = numWithInbox;
      mPrevious.numWithMediaSession = numWithMediaSession;
      mPrevious.numWithTitle = numWithTitle;
      mPrevious.numWithText = numWithText;
      mPrevious.numWithSubText = numWithSubText;
      mPrevious.numWithInfoText = numWithInfoText;
    }