boolean shouldUseReservedMetadataId() {
      return isMetadataChunk() && routerConfig.routerReservedMetadataEnabled && !RestUtils.isS3Request(restRequest);
    }
@return {@code true} If this chunk is a metadata chunk and router reserved metadata is enabled. {@code false}
otherwise.
ambry-router/src/main/java/com/github/ambry/router/PutOperation.java