Companion

companion object Companion : 
    WebSocketExtensionFactory<Config, WebSocketDeflateExtension>

key	`val key: AttributeKey<WebSocketDeflateExtension>` Key is used to locate extension.
rsv1	`val rsv1: Boolean` First extension bit used by current extension.
rsv2	`val rsv2: Boolean` Second extension bit used by current extension.
rsv3	`val rsv3: Boolean` Third extension bit used by current extension.

fun install(
    config: Config.() -> Unit
): WebSocketDeflateExtension

Create extension instance using config block. The extension instance is created for each WebSocket request.