code: @Override
      public CompletableFuture<Void> initialize(Duration timeout) {
          Preconditions.checkState(!this.initialized.get(), "TableMetadataStore is already initialized.");
  
          // Invoke submitAssignment(), which will ensure that the Metadata Segment is mapped in memory and pinned.
          // If this is the first time we initialize the TableMetadataStore for this SegmentContainer, a new id will be
          // assigned to it.
          val attributes = TableAttributes.DEFAULT_VALUES
                  .entrySet().stream()
                  .map(e -> new AttributeUpdate(e.getKey(), AttributeUpdateType.None, e.getValue()))
                  .collect(Collectors.toList());
          return submitAssignment(SegmentInfo.newSegment(this.metadataSegmentName, attributes), true, timeout)
                  .thenAccept(segmentId -> {
                      this.initialized.set(true);
                      log.info("{}: Metadata Segment pinned. Name = '{}', Id = '{}'", this.metadataSegmentName, segmentId);
                  });
      }
docs: region MetadataStore Implementation