Why suspend function is not allowed as supertype

What the difference if I extend simple function like this
typealias SimpleFunction = ()->Unit
class Foo : SimpleFunction …

but i cant extend suspend alias
typealias SuspendFunction = (suspend ()->Unit)

is this can be possible in the future or may be some of you know the hack )
Thanks in advice

Hello. We plan to support this in the future, please follow https://youtrack.jetbrains.com/issue/KT-18707 for updates.