Changes to eliminate future flattening

pkgs/pool/lib/pool.dart

diff --git a/pkgs/pool/lib/pool.dart b/pkgs/pool/lib/pool.dart
index 86f8363..ea3d2f0 100644
--- a/pkgs/pool/lib/pool.dart
+++ b/pkgs/pool/lib/pool.dart
@@ -122,7 +122,7 @@
     // synchronously in case the pool is closed immediately afterwards. Async
     // functions have an asynchronous gap between calling and running the body,
     // and [close] could be called during that gap. See #3.
-    return request().then<Future<T>>((resource) {
+    return request().then((resource) {
       return new Future<T>.sync(callback).whenComplete(resource.release);
     });
   }

pkgs/pool/pubspec.yaml

diff --git a/pkgs/pool/pubspec.yaml b/pkgs/pool/pubspec.yaml
index b9c5c8d..08f3b70 100644
--- a/pkgs/pool/pubspec.yaml
+++ b/pkgs/pool/pubspec.yaml
@@ -1,5 +1,5 @@
 name: pool
-version: 1.3.3
+version: 1.3.3-dev
 author: Dart Team <misc@dartlang.org>
 description: A class for managing a finite pool of resources.
 homepage: https://github.com/dart-lang/pool