add sanity check for block marshalling change
add sanity check for block marshalling change

ericflo/Sia,ChrisSchinnerl/Sia,ericflo/Sia,MrStrong/Sia,mharkus/Sia,mtlynch/Sia,ChrisSchinnerl/Sia,NebulousLabs/Sia,mharkus/Sia,NebulousLabs/Sia,mtlynch/Sia,MrStrong/Sia