Javadoc
Sets the number of shard copies that should be active for index creation to return.
Defaults to
ActiveShardCount#DEFAULT, which will wait for one shard copy
(the primary) to become active. Set this value to
ActiveShardCount#ALL to
wait for all shards (primary and all replicas) to be active before returning.
Otherwise, use
ActiveShardCount#from(int) to set this value to any
non-negative integer, up to the number of copies per shard (number of replicas + 1),
to wait for the desired amount of shard copies to become active before returning.
Index creation will only wait up until the timeout value for the number of shard copies
to be active before returning. Check
CreateIndexResponse#isShardsAcknowledged() to
determine if the requisite shard copies were all started before returning or timing out.