Example:

f()

async function f() {
    await g()
}

async function g() {
    await 42 // stack trace includes f without this line
    throw Error()
}

Prints:

Possibly unhandled promise rejection: Error
    at g (tmp/async.js:9:11)

f's stack frame is "lost", making debugging harder than it should be.

It should be possible to capture the stack in or around JS_EnqueueJob and stitch it back together in JS_ExecuteJob.

That obviously comes at some performance cost, so there should be a knob to control the length of the async stack trace, with zero meaning "off".

Up for the debate: the default setting of the knob.

The captured stack should be a rolling buffer where older entries drop off. Increase the reference count of JS functions when they're mixed into the captured stack, decrease them again when they drop off.