math/rand: add a Uint64 method #4254
Description
The Rand interface has methods for several types of random integers, including
uint32 and int63, but no uint64. I need random integers in [0, 2^64). I can of
course use two calls to Uint32 to do what I need, but see discussion here:
https://groups.google.com/group/golang-nuts/browse_thread/thread/2a57bcef8953d44a/335e3adb37bb4333
It would be nice to add this for 2.0, or whenever it's next okay to make a
break with the current API.