I'm trying to determine the best user experience of nyc supporting ES module loader hooks and I'm troubled by node.js not supporting multiple hooks. A substantial number of our users combine nyc with other transformations, `ts-node/register` being a common example. A common workflow is for users to run `nyc --require ts-node/register mocha` or `nyc mocha --require ts-node/register mocha`. In addition some test runners such as `ava` or `tap` which might automatically enable certain transformations for the user. One potential idea is that nyc could just not handle instrumentation of ES modules. We could create an `@istanbuljs/esm-transform` module and leave it to the end-user to enable the plugin. I'm concerned this will be a user experience regression compared to how nyc is commonly plug-n-play for CJS, also concerned about the complexity needed to document this. I acknowledge that complex loader hook composition would need to be done in user-space but it would be very nice for node.js to natively facilitate the most basic 'stack of hooks' use case. @nodejs/tooling @isaacs @novemberborn any comments from the view of test runners would be useful.