InMainThreadDecorator

interface Base{
  fun foo()
}

class BI : Base{
  override fun foo() {

  }

}
class InMainThreadThing (val b : Base, val handler: Handler) : Base by b{
  override fun foo() {
    accept { b.foo() }
  }
}

class Test{
  val x:InMainThreadThing = InMainThreadThing(BI(), Handler());
}

fun  InMainThreadThing.accept(f: () -> Unit ) {
  if (Looper.getMainLooper().thread == Thread.currentThread()) {
    f.invoke()
  } else {
    this.handler.post(f)
  }
}