Skip user/room assignment if unnecessary in bot

examples/simple_bot.rb

@@ -42,11 +42,11 @@ class MatrixBot
   end
 
   def on_message(message)
+    return unless message.content[:body] == '!ping'
+
     room = client.ensure_room message.room_id
     sender = client.get_user message.sender
 
-    return unless message.content[:body] == '!ping'
-
     puts "[#{Time.now.strftime '%H:%M'}] <#{sender.id} in #{room.id}> #{message.content[:body]}"
 
     origin_ts = Time.at(message[:origin_server_ts] / 1000.0)