Store Meta data with key

Imported Google Group message. Original thread at: Redirecting to Google Groups Import Date: 2016-01-19 21:19:38 +0000.
Sender:[email protected].
Date:Friday, 7 August 2015 00:28:40 UTC+1.

Is it possible to store in Tyk metadata of key when I create key?
In order to get access to metadata in middleware through session object.