boolean shouldLookupMetadataCache() {
    return (blobMetadataCache != null && isRangeRequest() && options.getBlobOptions.hasBlobSegmentIdx() == false
        && options.getBlobOptions.isRawMode() == false && blobId.getBlobDataType() == BlobId.BlobDataType.METADATA);
  }
Decides if we should look up the metadata cache during a GET request
@return True if and only if
 - cache exists
 - it is a RANGE request
 - it is not a raw mode request
 - it is not a GET request for a segment
 - the blobID is for a metadata blob (this info is present only in v5 and v6 version of blobID)
 False, otherwise.
ambry-router/src/main/java/com/github/ambry/router/GetBlobOperation.java