def statistics
      raise(ArgumentError, 'First call MessageConsumer::on_message with statistics: true before calling MessageConsumer::statistics()') unless @message_count
      duration = (@last_time || Time.now) - @start_time
      {
        messages:            @message_count,
        duration:            duration,
        messages_per_second: (@message_count/duration).to_i
      }
    end
def statistics
      raise(ArgumentError, 'First call MessageConsumer::on_message with statistics: true before calling MessageConsumer::statistics()') unless @message_count
      duration = (@last_time || Time.now) - @start_time
      {
        messages:            @message_count,
        duration:            duration,
        messages_per_second: (@message_count/duration).to_i
      }
    end
Return Statistics gathered for this listener