Kotlin/JS target `es2015` not usable with Workers

Kotlin [has a new `es2015` target][0] for Kotlin/JS. But, when used with [KotlinX coroutines][1], the compiler may generate code which uses `eval(...)`; dynamic code evaluation is not allowed on Workers.

It is not clear yet whether this issue arises from code generated by the compiler, or from KotlinX coroutines, or from somewhere else.

I have [filed an issue][2] with the Kotlin team corresponding to this one. I don't expect Cloudflare to open up `eval(...)`, so this is just a tracking issue until more information becomes available.

[0]: https://kotlinlang.org/docs/js-project-setup.html#support-for-es2015-features
[1]: https://github.com/Kotlin/kotlinx.coroutines
[2]: https://youtrack.jetbrains.com/issue/KT-71391/Cannot-use-es2015-in-restricted-environments