Reverse the message chain and return the former top-most message.
-> **Note:** Message chains are ordered in reverse-parsed order by default, i.e. the last parsed message is the message you'll receive from any call parsing HTTP messages.
+> ***NOTE:***
+> Message chains are ordered in reverse-parsed order by default, i.e. the last parsed message is the message you'll receive from any call parsing HTTP messages.
>
> This call re-orders the messages of the chain and returns the message that was parsed first with any later parsed messages re-parentized.