code: static Key getKey(boolean isLeft, int col, H2ONode node) {
      return Key.make("__radix_order__MSBNodeCounts_col" + col + "_node" + node.index() + (isLeft ? "_LEFT" : "_RIGHT"));
      // Each node's contents is different so the node number needs to be in the key
      // TODO: need the biggestBit in here too, that the MSB is offset from
    }
docs: make it homed to the owning node