code: void acceptOperation(StreamSegmentSealOperation operation) throws MetadataUpdateException {
          ensureSegmentId(operation);
          if (operation.getStreamSegmentOffset() < 0) {
              throw new MetadataUpdateException(containerId,
                      "StreamSegmentSealOperation cannot be accepted if it hasn't been pre-processed: " + operation);
          }
  
          this.sealed = true;
          this.isChanged = true;
      }
docs: Accepts a StreamSegmentSealOperation in the metadata.
  
  @param operation The operation to accept.
  @throws MetadataUpdateException  If the operation hasn't been pre-processed.
  @throws IllegalArgumentException If the operation is for a different Segment.