/**
 * The counters and histograms one replica keeps about the runs it executes, in Prometheus text.
 *
 * Written rather than imported, like the router: the server needs three metric kinds and a text
 * format, which is far smaller than any client library, and nothing here runs unless `/metrics` is
 * scraped.
 */
type Labels = Record<string, string>;
/** A replica's run counters and latency histograms. */
export declare class ServerMetrics {
    private readonly counters;
    private readonly histograms;
    /** Adds to a counter. */
    count(name: string, labels: Labels, by?: number): void;
    /** Records a duration, in seconds, in a histogram. */
    observe(name: string, labels: Labels, seconds: number): void;
    /** A counter's value for one set of labels, for tests and reports. */
    value(name: string, labels: Labels): number;
    /** Appends every counter and histogram to `lines`, with the help text given per name. */
    render(lines: string[], help: Record<string, string>): void;
}
/** Appends one gauge with its header. */
export declare function gauge(lines: string[], name: string, help: string, value: number, labels?: Labels): void;
/** One gauge with several labelled samples, under one header. Writes nothing without samples. */
export declare function gauges(lines: string[], name: string, help: string, samples: ReadonlyArray<[Labels, number]>): void;
export {};