code: PageEntry getEntryAt(int pos) {
          Preconditions.checkElementIndex(pos, getCount(), "pos must be non-negative and smaller than the number of items.");
          return new PageEntry(
                  this.data.subSegment(pos * this.config.entryLength, this.config.keyLength),
                  this.data.subSegment(pos * this.config.entryLength + this.config.keyLength, this.config.valueLength));
      }
docs: Gets a PageEntry representing the entry (Key + Value) at the given Position.
  
  @param pos The position to get the value at.
  @return A PageEntry containing the entry at the given Position. Note that the ByteArraySegments returned by this
  PageEntry's getKey() and getValue() are views inside a larger array and any modifications to that array will be
  reflected in them. If this value needs to be held for longer then it is recommended to get a copy of it (use getCopy()).