public static boolean isOriginatingDcRemote(BlobId blobId, ClusterMap clusterMap) {
    return blobId.getDatacenterId() != ClusterMap.UNKNOWN_DATACENTER_ID
        && blobId.getDatacenterId() != clusterMap.getLocalDatacenterId();
  }
@param blobId {@link BlobId} to check.
@param clusterMap {@link ClusterMap} object.
@return {@code true} if it can be determined that the blobid's originating dc is remote. {@code false} otherwise.
ambry-router/src/main/java/com/github/ambry/router/RouterUtils.java