public long getFutureReplicaOffsetLag() {
            return futureReplicaOffsetLag;
        }
The LEO of the replica - LEO of the future log of this replica in the destination log directory.
-1 if either there is not replica for this partition or the replica of this partition is not being moved to another log directory on the given broker.
clients/src/main/java/org/apache/kafka/clients/admin/DescribeReplicaLogDirsResult.java