# suspend

Defers creation of an `Fx` until each run begins.

## Signatures

```ts
export declare const suspend: <A, E, R>(fx: () => Fx<A, E, R>) => Fx<A, E, R>;
```

## Why

Recursive producers and producers whose definition depends on fresh mutable state
need laziness at the `Fx` boundary, not merely laziness of a value emission.

## Ownership and lifetime

`fx` is not evaluated during construction. It is evaluated once per run inside
`Effect.suspend`; thrown exceptions become Effect defects, and the returned
producer is owned and interrupted as part of that same run.

## Examples

```ts
import { collectAll, succeed, suspend } from "@typed/fx/Fx"

let next = 0
const source = suspend(() => succeed(++next))
const firstRun = collectAll(source)
const secondRun = collectAll(source)
```