# File lib/phusion_passenger/rack/out_of_band_gc.rb, line 46
  def call(env)
    status, headers, body = @app.call(env)

    @mutex.synchronize do
      @request_count += 1
      if @request_count == @frequency
        @request_count = 0
        headers['X-Passenger-Request-OOB-Work'] = 'true'
      end
    end
    
    [status, headers, body]
  end