code: private CompletableFuture<Void> reconcileAttributes(AggregatedAppendOperation op, TimeoutTimer timer) {
          // This operation must have previously succeeded if any of the following are true:
          // - If the Attribute Index is sealed, and so is our Segment.
          // - If the Attribute Index does not exist (deleted), and our Segment is deleted or a merged Transaction.
          return handleAttributeException(this.dataSource.persistAttributes(this.metadata.getId(), op.attributes, timer.getRemaining()));
      }
docs: Attempts to reconcile the attributes for a given operation. There is no verification done; this operation simply
  re-writes all the attributes to the index, which is much more efficient than trying to read the values from the
  index and then comparing them.
  
  @param op          The operation to reconcile.
  @param timer       Timer for the operation.
  @return A CompletableFuture that will indicate when the operation completed.