# RefDuration.isZero

Check if the current state of a RefDuration is zero.

## Signatures

```ts
export declare const isZero: <E, R>(ref: RefDuration<E, R>) => RefSubject.Computed<boolean, E, R>;
```

## Why

Check if the current state of a RefDuration is zero. The operation remains attached to the
RefSubject's versioned state boundary.

## Ownership and lifetime

The is zero view retains no independent state. An Effect read samples the source once; Fx
observation follows later pushes and its observing Scope owns subscription cleanup.