code: @Override
      @InterfaceAudience.Private
      public void changed(Database.ChangeEvent event) {
          final List<DocumentChange> changes = event.getChanges();
          supportExecutor.submit(new Runnable() {
              @Override
              public void run() {
                  submitRevisions(changes);
              }
          });
      }
docs: - (void) dbChanged: (NSNotification*)n in CBLRestPusher.m