/**
 * Observability
 * @namespace Core\Observable
 */
export default class Observability {
    /**
     * Factory method to create an instance of Observability.
     * @static
     * @param {object} options - Configuration options for initializing the observability agent.
     * @returns {Observability} - An instance of Observability.
     */
    static createObservabilityAgent(options: object): Observability;
    /**
     * Creates an instance of Observability with APM configurations.
     * @constructor
     * @param {object} options - Configuration options for initializing the APM client.
     * @param {string} options.serviceName - The name of the service being monitored.
     * @param {string} options.serverUrl - The URL of the APM server.
     * @param {boolean} [options.startApmAgent=false] - Whether to start the observability agent.
     * @param {string} [options.secretToken] - Secret token for the APM server.
     * @param {string} [options.environment='development'] - The environment in which the service is running.
     * @param {string} [options.logLevel='info'] - The log level for logging.
     */
    constructor(options: {
        serviceName: string;
        serverUrl: string;
        startApmAgent?: boolean | undefined;
        secretToken?: string | undefined;
        environment?: string | undefined;
        logLevel?: string | undefined;
    });
    /**
     * Starts the observability agent.
     */
    start(): void;
    /**
     * Middleware for capturing APM data and handling transactions.
     * @param {object} params - Parameters for the middleware.
     * @param {string} params.path - The path of the request.
     * @param {string} params.method - The HTTP method of the request.
     * @param {object} params.headers - The headers of the request.
     * @param {object} params.routeParams - The route parameters of the request.
     * @param {object} params.queryParams - The query parameters of the request.
     * @param {object} [params.payload] - The request payload.
     * @param {Function} callback - Callback function to be executed after middleware processing.
     * @param {object} httpListener - HTTP listener object with response handling functions.
     * @param {Function} httpListener.onFunction - Function that listens to HTTP events (e.g., 'finish').
     * @param {Function} httpListener.callback - Callback function to execute after the listener function.
     * @throws {Error} Throws error if there is an issue with processing.
     */
    middleware({ path, method, headers, routeParams, queryParams, payload }: {
        path: string;
        method: string;
        headers: object;
        routeParams: object;
        queryParams: object;
        payload?: object | undefined;
    }, callback: Function, httpListener: {
        onFunction: Function;
        callback: Function;
    }): Promise<void>;
    /**
     * Starts a new span for an existing transaction, typically for monitoring external requests or operations.
     * @param {string} spanName - The name of the span to be started.
     * @param {string} spanType - The type of the span (e.g., 'external', 'db').
     * @param {object} payload - The data sent or being treated in your span.
     * @returns {Object|null} - Returns a dummy span object or null.
     */
    startTransactionSpan(spanName: string, spanType: string | undefined, payload: object): Object | null;
    /**
     * Ends a given span and logs its duration for debugging purposes.
     * @param {object} span - The span object to be ended.
     * @throws {Error} Throws error if the span cannot be ended.
     * @example
     * observability.endTransactionSpan(span);
     */
    endTransactionSpan(span: object): Promise<void>;
    #private;
}