diff --git a/lib/sidekiq/processor.rb b/lib/sidekiq/processor.rb
index 7dc709e2..fe21e3be 100644
--- a/lib/sidekiq/processor.rb
+++ b/lib/sidekiq/processor.rb
@@ -14,6 +14,8 @@ module Sidekiq
     def self.middleware
       @middleware ||= begin
         chain = Middleware::Chain.new
+
+        # default middleware
         chain.register do
           use Middleware::Server::UniqueJobs, Sidekiq::Client.redis
           use Middleware::Server::Airbrake