We (Google Chrome team) are working on performance improvements on ServiceWorker, and we'd like to hear feedback for “ServiceWorker fetch fast-path” concept from the community.

The cost of ServiceWorker is not cheap, it can take up to hundreds of milliseconds to bootstrap the ServiceWorker itself and process fetch event handlers. "ServiceWorker fetch fast-path" reduces this cost by introducing the path that the request will immediately happen and go directly to the network, without waiting for the ServiceWorker bootstrap and bypass fetch handlers.

Please see the explainer for more details, and we've sent Intent to Experiment to the blink-dev group, to start the Origin Trial so that interested parties can join the experiment.

Our primary target is the main resource (navigation request). If the upcoming experiment brings good results, we will consider expanding this approach to specific subresources. Also, we don’t yet have a concrete idea for the proper API surface to enable this feature. Perhaps it will be the subset of the Declarative Routing API #1373 proposed by @jakearchibald or similar. Any feedback or API proposals are welcomed: for the main resource case, and for the subresource scenarios.