Add way to de-duplicate function calls

[chrisbanes]

I currently have a number of places where I request a specific URL. It would be nice if any concurrent requests would be de-duplicated so that any requests which are started while one is already in progress, joins the first and receives the same result.

I imagine that this would be similar to Go's singleflight: a collection wrapper around a Mutex, keyed on a string.

[elizarov]

Does it really has to be keyed by a string? We are not in Go, you know, we can do much better.

[chrisbanes]

Yeah agreed, although I do like the simplicity of a string. Using an inline class Key(val k: String) would work just as well though.

[LouisCAD]

I have to link this gist from @objcode, because it might help folks having this call de-duplicating use case: https://gist.github.com/objcode/7ab4e7b1df8acd88696cb0ccecad16f7#file-concurrencyhelpers-kt-L162-L339