code: @Override
      public SendQueue<T> sendQueueWithAutoFlush(int interval, TimeUnit timeUnit) {
          final SendQueue<String> sendQueue = queue.sendQueueWithAutoFlush(interval, timeUnit);
          return createJsonSendQueue(sendQueue);
      }
docs: Create a wrapper SendQueue that encoders the objects to JSON
  before putting them into the queue.
  
  @param interval interval
  @param timeUnit timeUnit
  @return returns wrapped SendQueue tht does JSON encoding.