Remove delegate_missing_to in FutureResult class and add test cases.

activerecord/lib/active_record/future_result.rb

@@ -60,7 +60,6 @@ def self.wrap(result)
     end
 
     delegate :empty?, :to_a, to: :result
-    delegate_missing_to :result
 
     attr_reader :lock_wait
 

activerecord/test/cases/relation/load_async_test.rb

@@ -217,6 +217,11 @@ def test_pluck
       assert_equal titles, Post.where(author_id: 1).load_async.pluck(:title)
     end
 
+    def test_count
+      count = Post.where(author_id: 1).count
+      assert_equal count, Post.where(author_id: 1).load_async.count
+    end
+
     def test_size
       expected_size = Post.where(author_id: 1).size
 
@@ -233,12 +238,19 @@ def test_empty?
       assert_predicate deferred_posts, :loaded?
     end
 
-    def test_load_async_with_query_cache
+    def test_load_async_pluck_with_query_cache
       titles = Post.where(author_id: 1).pluck(:title)
       Post.cache do
         assert_equal titles, Post.where(author_id: 1).load_async.pluck(:title)
       end
     end
+
+    def test_load_async_count_with_query_cache
+      count = Post.where(author_id: 1).count
+      Post.cache do
+        assert_equal count, Post.where(author_id: 1).load_async.count
+      end
+    end
   end
 
   class LoadAsyncNullExecutorTest < ActiveRecord::TestCase