wip fix race condition in AI code

Author: bpholt

twitter-futures/src/test/scala/com/dwolla/util/async/twitter/TwitterFutureAsyncMapKTests.scala

@@ -32,7 +32,11 @@ class TwitterFutureAsyncMapKTests extends CatsEffectSuite with ScalaCheckEffectS
   test("cancelling a running Twitter Future lifted into IO should interrupt the underlying Twitter Future") {
     for {
       promise <- IO(Promise[Int]())
-      fiber <- liftFuture[IO](IO.pure(promise)).start
+      startedLatch <- CountDownLatch[IO](1)
+      fiber <- IO.uncancelable { poll => // we only want the Future to be cancellable
+        poll(liftFuture[IO](startedLatch.release.as(promise))).start
+      }
+      _ <- startedLatch.await
       _ <- fiber.cancel
     } yield {
       assert(promise.isInterrupted.isDefined)