A modern programming language that makes developers happier.

kotlinlang

I'm perusing the source code for the coroutines library and I bumped into this on `CoroutineContext`:
```
Persistent context for the coroutine. It is an indexed set of [Element] instances.
An indexed set is a mix between a set and a map.
Every element in this set has a unique [Key]. Keys are compared _by reference_.
```
is there a reason for not using a `LinkedHashMap`?
what are the performance characteristics of an indexed set?

Just from reading this, I see keys compared by reference, which is much faster than `hashCode` which would be called in a `HashMap`

For couritinecontext, keys are compared by type (by the Companion object of that type), e.g like `coroutineContext[T]` = `coroutineContext[T.Companion]` and it returns a value of type `T?`.