docs: private boolean isMultiChunked(final String filename) {
        final FileCacheKey fileCacheKey = new FileCacheKey(indexName, filename, affinitySegmentId);
        final FileMetadata fileMetadata = metadataCache.get(fileCacheKey);
        if (fileMetadata==null) {
           //This might happen under high load when the metadata is being written
           //using putAsync; in such case we return true as it's the safest option.
           //Skipping the readlocks is just a performance optimisation, and this
           //condition is extremely rare.
           return true;
        }
        else {
           return fileMetadata.isMultiChunked();
        }
     }