/**
 * Private IoT SDK metrics module.
 *
 * Provides SDK-level metadata (version info) to pass to the CRT layer.
 * The CRT handles all feature detection (certificate source, TLS settings, etc.)
 * and embeds the combined metrics in the MQTT CONNECT packet username field.
 *
 * @internal
 */
import { AWSIoTMetrics } from "aws-crt/dist/common/mqtt_shared";
/**
 * Builds the SDK-level {@link AwsIoTDeviceSDKMetrics} payload that is passed
 * down to the CRT layer.
 *
 * The returned object carries SDK identity and the metrics format version
 * via two metadata entries:
 *
 * - `IoTSDKVersion`: the installed SDK package version, used to identify the
 *   SDK release on the server side.
 * - `IoTSDKMetricsVersion`: the metrics format version this SDK supports.
 *   The CRT only merges SDK-supplied features when this value matches the
 *   version it expects.
 *
 * The CRT layer is responsible for detecting connection-level features
 * (protocol version, certificate source, TLS settings, proxy type, etc.)
 * and appending them to the metadata before embedding the result in the
 * MQTT CONNECT packet username field.
 *
 * @returns A populated metrics object ready to attach to an MQTT5 client
 *          or MQTT3 connection configuration.
 *
 * @internal
 */
export declare function build_sdk_metrics(): AWSIoTMetrics;