Token call from membership PDF action does not provide the membership id to the tokens

Tthe token gets called from pdf but it doesn't know what token it is being called on. The best thing I can think of without a major refactor (over-due but not today) of token code is to allow the calling function to pass in additional params to CRM_Utils_Token::getTokenDetails which is the function responsible for 'filling out' the token details - including calling other functions. That way it could merge the passed params for each contact into the retrieved params before calling the hook