Represents a critical sound configuration that can be included in the `aps` dictionary of an APNs payload.

**Signature:**

    export interface CriticalSound 

## Properties

| Property | Type | Description |
|---|---|---|
| [critical](https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.criticalsound#criticalsoundcritical) | boolean | The critical alert flag. Set to `true` to enable the critical alert. |
| [name](https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.criticalsound#criticalsoundname) | string | The name of a sound file in the app's main bundle or in the `Library/Sounds` folder of the app's container directory. Specify the string "default" to play the system sound. |
| [volume](https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.criticalsound#criticalsoundvolume) | number | The volume for the critical alert's sound. Must be a value between 0.0 (silent) and 1.0 (full volume). |

## CriticalSound.critical

The critical alert flag. Set to `true` to enable the critical alert.

**Signature:**

    critical?: boolean;

## CriticalSound.name

The name of a sound file in the app's main bundle or in the `Library/Sounds` folder of the app's container directory. Specify the string "default" to play the system sound.

**Signature:**

    name: string;

## CriticalSound.volume

The volume for the critical alert's sound. Must be a value between 0.0 (silent) and 1.0 (full volume).

**Signature:**

    volume?: number;