    # File lib/rack/chunked.rb, line 53
        def call(env)
          status, headers, body = @app.call(env)
          headers = HeaderHash.new(headers)

          if ! chunkable_version?(env['HTTP_VERSION']) ||
             STATUS_WITH_NO_ENTITY_BODY.include?(status) ||
             headers[CONTENT_LENGTH] ||
             headers['Transfer-Encoding']
            [status, headers, body]
          else
            headers.delete(CONTENT_LENGTH)
            headers['Transfer-Encoding'] = 'chunked'
            [status, headers, Body.new(body)]
          end
        end