Avoid redundant thread creation by invoking coroutine timeout handlin…

…g code on Vert.x threads (#246) (#247)

By the way, it prevents from dispatching the coroutine execution to the context (because it's already executing on the right context).

Signed-off-by: Thomas Segismont <tsegismont@gmail.com>

vertx-lang-kotlin-coroutines/src/main/java/io/vertx/kotlin/coroutines/VertxCoroutine.kt

@@ -171,6 +171,10 @@ private class ContextCoroutineDispatcher(val vertxContext: ContextInternal) : Co
   override fun scheduleResumeAfterDelay(timeMillis: Long, continuation: CancellableContinuation<Unit>) {
     (delegate as Delay).scheduleResumeAfterDelay(timeMillis, continuation)
   }
+
+  override fun invokeOnTimeout(timeMillis: Long, block: Runnable, context: CoroutineContext): DisposableHandle {
+    return (delegate as Delay).invokeOnTimeout(timeMillis, block, context)
+  }
 }
 
 private class VertxScheduledFuture(