anchor.diff:     *
      * If the [_content] field is still `null`, get the content from the
      * content cache or from the [source]. If the content cannot be accessed
  -   * because of an exception, it considers to be an empty string.
  +   * because of an exception, it is considered to be an empty string.
      *
      * When a new content is read, the new [_contentHash] should be computed and
      * the current file state should be updated.
  
positive.code:           List<int> bytes = _byteStore.get(key);
            if (bytes != null) {
              PackageBundle linked = new PackageBundle.fromBuffer(bytes);
              store.addBundle(null, linked);
            } else {
              libraryUrisToLink.add(node.uri.toString());
            }
  
negative.code:       _content = driver._contentCache.getContents(source);
        _content ??= source.contents.data;
      } catch (_) {
        _content = '';
        // TODO(scheglov) We fail to report URI_DOES_NOT_EXIST.
        // On one hand we need to provide an unlinked bundle to prevent
        // analysis context from reading the file (we want it to work
        // hermetically and handle one one file at a time). OTOH,
        // ResynthesizerResultProvider happily reports that any source in the
        // SummaryDataStore has MODIFICATION_TIME `0`. We need to return `-1`
        // for missing files. Maybe add this feature to SummaryDataStore?
      }
      // Compute the content hash.
      List<int> textBytes = UTF8.encode(_content);
  