Arseniy Zhizhelev

Two ways to achieve this: 1. contact as object (singleton types). ``` val input ``` => ``` object input extends Contact ``` 2. tags ``` sealed trait Input val input...

We may want to first associate individual types with input/output contacts and then attempt to represent them as `HList` of inputs + `HList` of outputs.

There are many places of low quality code. `.sbt`, comments, deprecated features. We might want to fix those issues so that we have clean build.

FiberId.toSet is not stack safe

5

Current implementation of [`toSet`](https://github.com/zio/zio/blob/series/2.x/core/shared/src/main/scala/zio/FiberId.scala#L75): ```scala final def toSet: Set[FiberId.Runtime] = self match { case None => Set.empty[FiberId.Runtime] case id @ Runtime(_, _, _) => Set(id) case Composite(l, r) => l.toSet...