Change stage in the Base.shutdown() method to that all parsers stop processing input.

lib/websocket/driver.rb

@@ -130,6 +130,7 @@ module WebSocket
 
     def shutdown(code, reason)
       @ready_state = 3
+      @stage = 5
       emit(:close, CloseEvent.new(code, reason))
     end
 

lib/websocket/driver/hybi.rb

@@ -258,7 +258,6 @@ module WebSocket
       def shutdown(code, reason)
         frame(reason, :close, code) if @ready_state < 2
         @frame = @message = nil
-        @stage = 5
         @extensions.close
         super
       end