# merge

Merge another struct into the current state of a RefStruct.

## Signatures

```ts
export declare const merge: {
    <O extends object>(that: O): <S extends object, E, R>(ref: RefStruct<S, E, R>) => Effect.Effect<S, E, R>;
    <S extends object, O extends object, E, R>(ref: RefStruct<S, E, R>, that: O): Effect.Effect<S, E, R>;
};
```

## Why

Combines bulk struct changes in one committed value, giving subscribers one coherent update
rather than a partially applied sequence.

## Ownership and lifetime

Running merge performs one serialized struct transition and resolves with its committed value.
It acquires no resource; failures and services remain those of the source ref.