SR: Control event to get the shared random values
Once all dirauth move to 029, the consensus will have a shared random value regurlarly. Having a way to get that value through the control port would be useful for many purposes including people wanting to use that value outside of tor.
I recommend we implement that only in 030 so we'll have a full stable version to debug and make sure it actually works properly before we expose it to a wider audience.
This ticket is the main one for both the spec and implementation.