Add sample of Observable interoperability

src/main/kotlin/interop/observable/ObservableInterop.kt

@@ -0,0 +1,18 @@
+package interop.observable
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.rx2.rxObservable
+import kotlin.coroutines.CoroutineContext
+
+class ObservableInterop(
+    override val coroutineContext: CoroutineContext = Dispatchers.Default
+): CoroutineScope {
+    fun getStream() = CoroutineScope(coroutineContext).rxObservable {
+        (1..10).map {
+            delay(100)
+            send(it)
+        }
+    }
+}

src/main/kotlin/interop/observable/TestObservableInterop.kt

@@ -0,0 +1,9 @@
+package interop.observable
+
+fun main() {
+    println("Creating ObservableInterop")
+    val observableInterop = ObservableInterop()
+    observableInterop.getStream().subscribe(::println, ::println)
+
+    Thread.sleep(2000)
+}