code: public static long sizeOf(Struct sct) {
  	Iterator<Entry<Key, Object>> it = sct.entryIterator();
  	Entry<Key, Object> e;
  	long size = 0;
  	while (it.hasNext()) {
  	    e = it.next();
  	    size += SizeOf.size(e.getKey());
  	    size += SizeOf.size(e.getValue());
  	}
  	return size;
      }
docs: return the size of given struct, size of values + keys
  
  @param sct
  @return