don't store empty shards
don't store empty shards

jcrist/dask,mraspaud/dask,simudream/dask,freeman-lab/dask,mraspaud/dask,cowlicks/dask,ContinuumIO/dask,cpcloud/dask,dask/dask,gameduell/dask,pombredanne/dask,wiso/dask,PhE/dask,vikhyat/dask,esc/dask,hainm/dask,jakirkham/dask,blaze/dask,mikegraham/dask,pombredanne/dask,simudream/dask,ssanderson/dask,mrocklin/dask,marianotepper/dask,PhE/dask,clarkfitzg/dask,jakirkham/dask,freeman-lab/dask,ContinuumIO/dask,wiso/dask,clarkfitzg/dask,minrk/dask,minrk/dask,blaze/dask,jcrist/dask,jayhetee/dask,jayhetee/dask,ssanderson/dask,esc/dask,vikhyat/dask,chrisbarber/dask,dask/dask,marianotepper/dask,mrocklin/dask,hainm/dask