public List<ReplicaThread.RemoteReplicaGroup> getInflightRemoteReplicaGroups() {
    return getGroupTrackers().stream()
        .filter(GroupTracker::isInFlight)
        .map(GroupTracker::getRemoteReplicaGroup)
        .collect(Collectors.toList());
  }
@return returns remote replica groups that are getting tracked in group trackers of
this data node tracker
ambry-replication/src/main/java/com/github/ambry/replication/continuous/DataNodeTracker.java