code: long storeSpaceForAdd() {
          return LinkedList.maximumSerializedSize() // List header.
                 + 3 * LinkedList.Link.maximumSerializedSize() // Current,Previous,Next links.  
                 + 4 * owningToken.objectStore.getAddSpaceOverhead() // Store overhead for all of the above.
                 + storeSpaceForRemove(); // In case we backout the add.
      }
docs: The space we reserve in the ObjectStore before we begin an add operation.
  
  @return long a worst case estimate of the ObjectStore space needed to add an entry
  to this list.