targetShardCount int32,
sourceShardID int32,
if sourceShardCount%targetShardCount != 0 && targetShardCount%sourceShardCount != 0 {
panic(fmt.Sprintf("cannot map shard ID between source & target shard count: %v vs %v",
sourceShardCount, targetShardCount))
}
if sourceShardCount < targetShardCount {
// one to many
// 0-3