Kotlin 1.1 supports coroutines what IHMO makes concurrency in a GUI much nicer. For example, it has C# like async/await methods; but more flexible...
Which allows full control how async/await works, kind of like on the upcoming C++ co-routines, where async/await become syntactic sugar for blessed data structure.
EDIT: Should have provided the actual information.
The feature as introduced in C# 7 is called "Generalized async return types".