import { Request } from '../request/request';
export declare class Tracer {
    private _serviceName;
    private _enabled;
    private _ctxImpl;
    private _reporter;
    private _tracer;
    constructor(_serviceName: string);
    trace(req: Request): Function;
    private _getHeadersFromRequest;
    private _getHeadersForRequest;
    private _getZipkinHost;
}