Payload Parser - time variable

Payload Parser - time variable

Hello,
I can use some help / sample code if possible (consider me a newbie ! when it come to writing code).

I have my sensor reporting 'time'  (device time)  as part of the payload data.
I would like to change the value of this 'device time' to  $TIME$ (the time data was received).

What would the custom parser snippet look like ?

Thank you in advance .

-------
Long version:-  I am using dragino sensors with Helium, to the best of my knowledge there is no simple way to sync the device time clock .. (unless i am missing something) ... hence I am looking to correct this via payload parser ..
If someone has a better suggestion, I am all ears !.
-------
Faisal