"using" field of protobuf message is not wired up (currently has value 0)

In indexer logs, I came across logs like -

2015-09-03T14:48:33.528Z+05:30 [Info] KVSender::sendMutationTopicRequest Projector 172.16.1.218:10000 Topic INIT_STREAM_TOPIC_f1:3a:4c:dc:1e:a3:2:b8 default
Instances [indexInstance:<instId:1009605148002059602 state:IndexPending definition:<defnID:1009605148002059602 bucket:"default" isPrimary:true name:"index_p1" using:0 exprType:N1QL partitionScheme:SINGLE partnExpression:"" whereExpression:"" > singlePartn:<endpoints:"127.0.0.1:9109" > > ]

where using value is 0 and state is IndexPending . Also another log -

015-09-03T14:48:35.433Z+05:30 [Info] KVSender::sendAddInstancesRequest Projector 172.16.1.218:10000 Topic MAINT_STREAM_TOPIC_f1:3a:4c:dc:1e:a3:2:b8
Instances [indexInstance:<instId:1009605148002059602 state:IndexLoading definition:<defnID:1009605148002059602 bucket:"default" isPrimary:true name:"index_p1" using:0 exprType:N1QL partitionScheme:SINGLE partnExpression:"" whereExpression:"" > singlePartn:<endpoints:"127.0.0.1:9111" > > ]

where state is IndexLoading.

The using being 0 does not impact in anyway as it is not used by projector. But it can be set to gsi or memdb to be consistent.