System.ServiceModel 4.0.0.0 System.Enum To be added. Specifies an enumeration of WebSocket transport usage. Field 4.0.0.0 System.ServiceModel.Channels.WebSocketTransportUsage Indicates WebSocket transport will always be used. Field 4.0.0.0 System.ServiceModel.Channels.WebSocketTransportUsage Indicates WebSocket transport will never be used. Field 4.0.0.0 System.ServiceModel.Channels.WebSocketTransportUsage Indicates WebSocket transport will be used for duplex service contracts only.