Instead use regular NetworkResourceLoader and create a PingLoad for any request that has keepAlive equal to true.
Created attachment 331383 [details] Patch
Comment on attachment 331383 [details] Patch Attachment 331383 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-queues.webkit.org/results/6092884 Number of test failures exceeded the failure limit.
Created attachment 331384 [details] Archive of layout-test-results from ews104 for mac-sierra-wk2 The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews. Bot: ews104 Port: mac-sierra-wk2 Platform: Mac OS X 10.12.6
Comment on attachment 331383 [details] Patch Attachment 331383 [details] did not pass ios-sim-ews (ios-simulator-wk2): Output: http://webkit-queues.webkit.org/results/6092936 Number of test failures exceeded the failure limit.
Created attachment 331386 [details] Archive of layout-test-results from ews124 for ios-simulator-wk2 The attached test failures were seen while running run-webkit-tests on the ios-sim-ews. Bot: ews124 Port: ios-simulator-wk2 Platform: Mac OS X 10.12.6
Created attachment 331484 [details] WIP