export declare const counter: (_key: MetricKey.MetricKey.Counter) => MetricHook.Counter

export declare const frequency: (_key: MetricKey.MetricKey.Frequency) => MetricHook.Frequency

export declare const gauge: (_key: MetricKey.MetricKey.Gauge, startAt: number) => MetricHook.Gauge

export declare const histogram: (key: MetricKey.MetricKey.Histogram) => MetricHook.Histogram

export declare const make: <In, Out>(options: {
  readonly get: LazyArg<Out>
  readonly update: (input: In) => void
}) => MetricHook<In, Out>

export declare const summary: (key: MetricKey.MetricKey.Summary) => MetricHook.Summary

export interface MetricHook<In, Out> extends MetricHook.Variance<In, Out>, Pipeable {
  readonly get: () => Out
  readonly update: (input: In) => void
}

export declare const MetricHookTypeId: typeof MetricHookTypeId

export type MetricHookTypeId = typeof MetricHookTypeId

export interface Variance<In, Out> {
  readonly [MetricHookTypeId]: {
    readonly _In: (_: In) => void
    readonly _Out: (_: never) => Out
  }
}

export type Counter = MetricHook<number, MetricState.MetricState.Counter>

export type Frequency = MetricHook<string, MetricState.MetricState.Frequency>

export type Gauge = MetricHook<number, MetricState.MetricState.Gauge>

export type Histogram = MetricHook<number, MetricState.MetricState.Histogram>

export type Root = MetricHook<any, MetricState.MetricState.Untyped>

export type Summary = MetricHook<readonly [number, number], MetricState.MetricState.Summary>

export type Untyped = MetricHook<any, any>

export declare const onUpdate: {
  <In, Out>(f: (input: In) => void): (self: MetricHook<In, Out>) => MetricHook<In, Out>
  <In, Out>(self: MetricHook<In, Out>, f: (input: In) => void): MetricHook<In, Out>
}