support empty iterables in unpack rmeote_data
support empty iterables in unpack rmeote_data

broxtronix/distributed,blaze/distributed,amosonn/distributed,dask/distributed,amosonn/distributed,dask/distributed,broxtronix/distributed,dask/distributed,mrocklin/distributed,amosonn/distributed,broxtronix/distributed,mrocklin/distributed,dask/distributed,blaze/distributed,mrocklin/distributed