code: public static Value STORE_get( Key key ) {
      Value val = H2O.STORE.get(key);
      if( val == null ) return null; // A true null
      if( !val.isNull() ) return val; // Not a special Null
      // One-shot throwaway attempt at upgrading the special Null to a true null
      if( val._rwlock.get()==0 ) H2O.putIfMatch(key,null,val);
      return null;                // Special null, but missing from callers point of view
    }
docs: Return the not-Null value, or the true null.