Prepend task to shared chain

[sandrwich]

Is it currently possible to insert into shared chain at the beginning, not the end? I'm using taskchain for queue-like thing and I need to make some tasks high priority.

In the current scenario, I'm adding things to the queue like this:

sharedChain.async(..).asyncFirstCallback(..).sync(..).execute()

[aikar]

Currently no, but PR's welcome for something like newSharedChain(id, true) where true = queueHead that defaults to false.