return l.Zone == o.Zone &&
			l.Region == o.Region
	}
}

func MatchRegion(l Instance) Match {
	return func(o Instance) bool {
		return l.Region == o.Region
	}
}

func MatchOtherZoneInSameRegion(l Instance) Match {
	return And(MatchRegion(l), Not(MatchZone(l)))
}

func And(m1 Match, m2 Match) Match {
	return func(o Instance) bool {
		return m1(o) && m2(o)
	}
}

	clientLocality := c.Locality()
	clientLatency := clientLatencies[0]

	nodesSameZone := s.mesh.Nodes().Select(locality.MatchZone(clientLocality))
	nodesSameRegion := s.mesh.Nodes().Select(locality.MatchOtherZoneInSameRegion(clientLocality))
	nodesOtherRegion := s.mesh.Nodes().Select(locality.Not(locality.MatchRegion(clientLocality)))

	// Store in the output.
	qLatency := s.mesh.Nodes().QueueLatency().Data()