KAYAK-1398 Use interruptible for send

[amohrland]

KAYAK-1398 This is a first pass for low-hanging blocking fruit.

[amohrland]

I've updated this to instead use interruptible(many = false), since Producer#send respects thread interruption:

InterruptException - If the thread is interrupted while blocked

[amohrland]

Since this is new and introduces some risk, I'm going to wait till we've determined that ce3 is stable in prod before merging.

[amohrland]

A blast from the past

[zcox]

Heh I noticed this today too. You were 2.5 years ahead!