code: func (p *UnitStatePublisher) queueForPublish(name string, us *unit.UnitState) {
  	p.toPublishMutex.Lock()
  	p.toPublishStates[name] = us
  	p.toPublishMutex.Unlock()
  	// This may block for some time, but even if it occurs after
  	// the above UnitState has already been published, it will
  	// simply trigger a no-op
  	p.toPublish <- name
  }
docs: // queueForPublish notifies the publishing goroutines that a particular
  // UnitState should be published to the Registry. This can block and should be
  // called in a goroutine.