Function when

fdbserver/BackupWorker.actor.cpp:463–470

			choose {
				when(wait(self->cx->onProxiesChanged())) {}
				when(GetReadVersionReply reply =
				         wait(basicLoadBalance(self->cx->getGrvProxies(UseProvisionalProxies::False),
				                               &GrvProxyInterface::getConsistentReadVersion,
				                               request,
				                               self->cx->taskID))) {
					self->cx->ssVersionVectorCache.applyDelta(reply.ssVersionVectorDelta);
					return reply.version;
				}
			}
		}
	}