checkDatastreamLabel(dsLabel);
w = m_manager.getWriter(Server.USE_DEFINITIVE_STORE, context, pid);
org.fcrepo.server.storage.types.Datastream orig =
w.GetDatastream(datastreamId, null);
if (orig == null) {
throw new DatastreamNotFoundException("Object " + pid + " has no datastream "
+ datastreamId + " to modify");
}
// if provided, check request lastModifiedDate against the datastream,
// rejecting the request if the datastream's mod date is more recent.
if (lastModifiedDate != null) {