async_hooks: add AsyncResource.bindCurrent()

[bengl]

This new static method does roughly the same thing as AsyncResource.bind(), except that it does not create a new AsyncResource. Instead, it relies on the existing current one.

This is an optimization useful in basically any situation where bind() would be called without passing (or relying on) the type argument.

I opted to make a completely different method, rather than overload bind() even more than it already is, but I can change that if desired.

[targos]

@nodejs/async_hooks

[vdeturckheim]

When would one use bindCurrent instead of bind ?

[bengl]

Almost any time you'd think you'd want to use the static bind. It avoids the creation of a new AsyncResource instance, which in many cases isn't actually needed.

[targos]

Should we explain in the documentation when bind is actually needed?

[bengl]

Another option here would be to make bind() avoid creating a new AsyncResource when type is not provided. That would potentially be a semver-major change (although the docs make no guarantees of resources being created), but perhaps warranted?

[bengl]

Converted this to a draft, because I'd like to explore just modifying bind()'s behaviour first. That would arguably be semver-patch, since neither the docs nor the tests make any assertions about whether a new AsyncResource is created when type is not provided.

[bengl]

Closing this in favour of #43065. It turned out this approach (i.e. replacing the the new AsyncResource() with calls to executionAsyncResource(), etc.) wasn't particularly beneficial.