Merge pull request ReactiveX#2880 from davidmoten/reduce-optimization

Use singleton reduction functions in count and countLong

Author: zsxwing

src/main/java/rx/Observable.java

@@ -3630,12 +3630,16 @@ public final Boolean call(T t1) {
      * @see #countLong()
      */
     public final Observable<Integer> count() {
-        return reduce(0, new Func2<Integer, T, Integer>() {
+        return reduce(0, CountHolder.INSTANCE);
+    }
+    
+    private static final class CountHolder {
+        static final Func2<Integer, Object, Integer> INSTANCE = new Func2<Integer, Object, Integer>() {
             @Override
-            public final Integer call(Integer t1, T t2) {
-                return t1 + 1;
+            public final Integer call(Integer count, Object o) {
+                return count + 1;
             }
-        });
+        };
     }
 
     /**
@@ -3657,14 +3661,18 @@ public final Integer call(Integer t1, T t2) {
      * @see #count()
      */
     public final Observable<Long> countLong() {
-        return reduce(0L, new Func2<Long, T, Long>() {
+        return reduce(0L, CountLongHolder.INSTANCE);
+    }
+
+    private static final class CountLongHolder {
+        static final Func2<Long, Object, Long> INSTANCE = new Func2<Long, Object, Long>() {
             @Override
-            public final Long call(Long t1, T t2) {
-                return t1 + 1;
+            public final Long call(Long count, Object o) {
+                return count + 1;
             }
-        });
+        };
     }
-
+    
     /**
      * Returns an Observable that mirrors the source Observable, except that it drops items emitted by the
      * source Observable that are followed by another item within a computed debounce duration.