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# SessionPropertyKey

A protocol for defining a custom session property key.

```
protocol SessionPropertyKey : SendableMetatype
```

## Topics

### Inspecting a property key

[`static var defaultValue: Self.Value`](/documentation/FoundationModels/SessionPropertyKey/defaultValue)

The default value of the property key.

[`associatedtype Value`](/documentation/FoundationModels/SessionPropertyKey/Value)

The type of value that represent this property key.

## Relationships

### Inherits From

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

---

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