Caffe2: do we have a way or example to use those MPI ops provided by caffe2?

i find there’re some native MPI ops under: caffe2/mpi path. Just wonder if this ops have been verified on multi-nodes environment. or do we have an example to show how to use it?

BTW i have checked the example ‘resnet50_trainer.py’, but seems it only support Gloo engine way.