Returns a new balancer which is represented by a com.twitter.finagle.ServiceFactory.
Returns a new balancer which is represented by a com.twitter.finagle.ServiceFactory.
The load balancer's collection is usually populated concurrently. So the interface to build a balancer is wrapped in an com.twitter.util.Activity which allows us to observe this process for changes.
The StatsReceiver which balancers report stats to. See com.twitter.finagle.loadbalancer.Balancer to see which stats are exported across implementations.
The exception returned when a balancer's collection is empty.