code: private final void buildIfNeededMap() {
          if ( map == null ) {
              map = new HashMap<>( items.length );
  
              for ( Entry<String, Value> miv : items ) {
                  if ( miv == null ) {
                      break;
                  }
                  map.put( miv.getKey(), miv.getValue() );
              }
          }
      }
docs: Build the map if requested to, it does this lazily.