import { Metric, Fields } from '../index';
export declare class Gauge implements Metric {
    private readFn?;
    private _value?;
    _init(): void;
    /**
     * Use a read function to retrieve value on read.
     */
    from(readFn: () => number): void;
    /**
     * Set current value. The value is ignore if a read function is given in `from()`.
     */
    value(value: number): void;
    _read(): Fields | undefined;
}