function seekMetadataLRU(self) {
			while (self._lru <= self._mru && self._metadata.__byIndex__[self._lru] == undefined) {
				self._lru++;
			}
			// The lru should never skip item. So current value should always point to the 1st (numeric order) non-empty
			// item in self._metadata.__byIndex map
			return (self._lru <= self._mru);
		}
Moves the pointer of LRU to the next available (non-empty) item starting from the current position.
@returns {boolean} true if the seek moved the pointer to an existing item, false - if no item is found