function getCacheKey(request) {
	  var service = request.service;
	  var api = service.api || {};
	  var operations = api.operations;
	  var identifiers = {};
	  if (service.config.region) {
	    identifiers.region = service.config.region;
	  }
	  if (api.serviceId) {
	    identifiers.serviceId = api.serviceId;
	  }
	  if (service.config.credentials.accessKeyId) {
	    identifiers.accessKeyId = service.config.credentials.accessKeyId;
	  }
	  return identifiers;
	}
Generate key (except resources and operation part) to index the endpoints in the cache
If input shape has endpointdiscoveryid trait then use
  accessKey + operation + resources + region + service as cache key
If input shape doesn't have endpointdiscoveryid trait then use
  accessKey + region + service as cache key
@return [map<String,String>] object with keys to index endpoints.
@api private