1 files changed, 6 insertions, 4 deletions
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 5697282791..5247e61a23 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -41,7 +41,7 @@ module ActionDispatch # :nodoc:
 
     # Get and set headers for this response.
     attr_accessor :header
-    
+
     alias_method :headers=, :header=
     alias_method :headers,  :header
 
@@ -181,9 +181,9 @@ module ActionDispatch # :nodoc:
     end
     alias_method :status_message, :message
 
-    def respond_to?(method)
+    def respond_to?(method, include_private = false)
       if method.to_s == 'to_path'
-        stream.respond_to?(:to_path)
+        stream.respond_to?(method)
       else
         super
       end
@@ -210,7 +210,9 @@ module ActionDispatch # :nodoc:
       if body.respond_to?(:to_path)
         @stream = body
       else
-        @stream = build_buffer self, munge_body_object(body)
+        synchronize do
+          @stream = build_buffer self, munge_body_object(body)
+        end
       end
     end