docs: public String setNodeAvailableForSessionId(final String sessionId, final boolean available) {
  		if ( _nodeIdService != null && isEncodeNodeIdInSessionId() ) {
  			final String nodeId = _sessionIdFormat.extractMemcachedId(sessionId);
  			if ( nodeId != null ) {
  				_nodeIdService.setNodeAvailable(nodeId, available);
  				return nodeId;
  			}
  			else {
  				LOG.warn("Got sessionId without nodeId: " + sessionId);
  			}
  		}
  		return null;
  	}