Support primitives in Flow#collectType

[JD557]

Flow#collectType was not working as expected for primitives. This PR replaces the use of ClassTag#runtimeClass#instanceOf with ClassTag#unapply.

While the default implementation of ClassTag#unapply simply defers to ClassTag#runtimeClass#instanceOf, this is not the case for the ClassTags of primitives, which only override unapply.

See the IntManifest for an example:

https://github.com/scala/scala/blob/v2.13.14/src/library/scala/reflect/Manifest.scala#L223-L236

[raboof]

nice!

[pjfanning]

lgtm - merging, thanks @JD557

[pjfanning]

Is this something that we should consider backporting to the 1.0.x relaeses?

[JD557]

Is this something that we should consider backporting to the 1.0.x relaeses?

That's obviously up to you (the maintainers) to decide, but my gut feeling says that maybe not.

Mostly because it changes the behavior from Akka (I doubt anyone depended on this behavior, though) and it's not that hard to fix with a normal collect.

I actually imagine most people just use collect and don't even notice that this method exists (at least that's how I stumbled on the bug 😅)