Class
Common
```kotlin
@ExperimentalFoundationStyleApi
open class StyleStateKey(internal val defaultValue: T)
```
The key to a `StyleState` value. A `StyleState` is a map from `StyleStateKey` to the current
value of the style state and the current value can be retrieved from a `StyleState` using array
index syntax or calling `StyleState.get` directly.
A `StyleStateKey` can be used to create a custom value that can be used in a `Style` to provide
properties based on the state of the value.
There are a set of predefined states that are expected to be commonly provided by elements that
are styleable, `StyleStateKey.Pressed`, `StyleStateKey.Hovered`, `StyleStateKey.Toggle`,
`StyleStateKey.Enabled`, and `StyleStateKey.Selected`. The `StyleState` provides helper
properties for these states, `StyleState.isPressed`, `StyleState.isHovered`, etc.
It is recommended that any new `StyleStateKey` be a constant with at least the same accessibility
as the component that uses it. It is also recommended to have a corresponding extension functions
for `StyleState` to allow a style to more easily access the state. For example, if a
`StyleStateKey` is added for a "playing" state, such as `var PlayingStateKey =
styleStateKey(false)` then it is recommended for a `val StyleState.isPlaying =
this.get(PlayingStateKey)` to be declared.
It is also recommended that an extension function for `StyleScope` also be created that allows
the style`fun StyleScope.playing(block: StyleScope.() -> Unit)` be declared that will only call
`block` when the `StyleState.isPlaying` is `true`.
## Companion Object
#### Properties
Common
```kotlin
val Pressed: StyleStateKey
```
The style state key for the pressed state of a state.
This state is `true` when the style component is pressed
Common
```kotlin
val Hovered: StyleStateKey
```
The style state key for the hovered state of a style.
Common
```kotlin
val Focused: StyleStateKey
```
The style state key for the focused state of a style.
Common
```kotlin
val Selected: StyleStateKey
```
The style state key for the selected state of a style.
Common
```kotlin
val Enabled: StyleStateKey
```
The style state key for the enabled state of a style.
Common
```kotlin
val Toggle: StyleStateKey
```
The style state key for the hovered state of a style.