Try to record "performance". 

Here's the exception i get whenever I hit "stop": 

Uncaught (in promise) DOMException: Failed to construct 'SharedWorker': The location of the SharedWorker named 'utility_shared_worker' does not exactly match the provided URL ('chrome-devtools://devtools/custom/utility_shared_worker.js').
    at Services.ServiceManager.createAppService (chrome-devtools://devtools/custom/services/ServiceManager.js:39:35)
    at Function.ensureTempStorageCleared (chrome-devtools://devtools/custom/bindings/TempFile.js:124:35)
    at Function.create (chrome-devtools://devtools/custom/bindings/TempFile.js:110:30)
    at new Bindings.DeferredTempFile (chrome-devtools://devtools/custom/bindings/TempFile.js:236:23)
    at Bindings.TempFileBackingStorage._flush (chrome-devtools://devtools/custom/bindings/TempFile.js:467:20)
    at Bindings.TempFileBackingStorage.finishWriting (chrome-devtools://devtools/custom/bindings/TempFile.js:478:10)
    at SDK.TracingModel.tracingComplete (chrome-devtools://devtools/custom/sdk/TracingModel.js:140:26)
    at Timeline.TimelineController._allSourcesFinished (chrome-devtools://devtools/custom/timeline/TimelineController.js:243:24)
    at Promise.all.then (chrome-devtools://devtools/custom/timeline/TimelineController.js:91:57)