Provide way to dedup function calls

[recheej]

Resolves #1097.

I think naming can def change. Open to suggestions. Let me know what you think for API. Btw, how do you update kotlinx-coroutines-core.api?

[elizarov]

You are proposing to add some quite massing public API without any docs. It does not work this way. Can you, please, start by explaining the design goals of this PR. What exact problem does it solve? How generic it is? Why it has to add some new public classes to the API?

[recheej]

@elizarov sure I can provide more documentation. First, it should be known that I'm trying to replicate api from go as mentioned in the issue. But sounds like you maybe have issue with new public classes? Mind giving me your thoughts there before I go adding all this documentation to this public class that may be remove in the end?

[recheej]

Closing issue as it's required by maintainers that things like this come with a design write up. While I understand the need it's too much investment for me right now.