1.x: Enabled Single onSubscribeStart hook

Author: phajduk

src/main/java/rx/Single.java

@@ -1569,14 +1569,12 @@ public final void onNext(T args) {
      * @param subscriber
      *            the Subscriber that will handle the emission or notification from the Single
      */
-    public final void unsafeSubscribe(Subscriber<? super T> subscriber) {
+    public final Subscription unsafeSubscribe(Subscriber<? super T> subscriber) {
         try {
             // new Subscriber so onStart it
             subscriber.onStart();
-            // TODO add back the hook
-            //            hook.onSubscribeStart(this, onSubscribe).call(subscriber);
-            onSubscribe.call(subscriber);
-            hook.onSubscribeReturn(subscriber);
+            hook.onSubscribeStart(this, onSubscribe).call(subscriber);
+            return hook.onSubscribeReturn(subscriber);
         } catch (Throwable e) {
             // special handling for certain Throwable/Error/Exception types
             Exceptions.throwIfFatal(e);
@@ -1593,6 +1591,7 @@ public final void unsafeSubscribe(Subscriber<? super T> subscriber) {
                 // TODO why aren't we throwing the hook's return value.
                 throw r;
             }
+            return Subscriptions.unsubscribed();
         }
     }
 
@@ -1660,9 +1659,7 @@ public final Subscription subscribe(Subscriber<? super T> subscriber) {
         // The code below is exactly the same an unsafeSubscribe but not used because it would add a sigificent depth to alreay huge call stacks.
         try {
             // allow the hook to intercept and/or decorate
-            // TODO add back the hook
-            //            hook.onSubscribeStart(this, onSubscribe).call(subscriber);
-            onSubscribe.call(subscriber);
+            hook.onSubscribeStart(this, onSubscribe).call(subscriber);
             return hook.onSubscribeReturn(subscriber);
         } catch (Throwable e) {
             // special handling for certain Throwable/Error/Exception types

src/main/java/rx/plugins/RxJavaSingleExecutionHook.java

@@ -61,11 +61,11 @@ public <T> Single.OnSubscribe<T> onCreate(Single.OnSubscribe<T> f) {
      * logging, metrics and other such things and pass-thru the function.
      *
      * @param onSubscribe
-     *            original {@link Single.OnSubscribe}<{@code T}> to be executed
-     * @return {@link Single.OnSubscribe}<{@code T}> function that can be modified, decorated, replaced or just
+     *            original {@link Observable.OnSubscribe}<{@code T}> to be executed
+     * @return {@link Observable.OnSubscribe}<{@code T}> function that can be modified, decorated, replaced or just
      *         returned as a pass-thru
      */
-    public <T> Single.OnSubscribe<T> onSubscribeStart(Single<? extends T> singleInstance, final Single.OnSubscribe<T> onSubscribe) {
+    public <T> Observable.OnSubscribe<T> onSubscribeStart(Single<? extends T> singleInstance, final Observable.OnSubscribe<T> onSubscribe) {
         // pass-thru by default
         return onSubscribe;
     }