 					observer.send(error: err)
 					return
 				}
-				guard case let SessionResponse.previewUpdate(initData) = response else { fatalError("invalid response data") }
+				guard case let SessionResponse.previewInitialized(initData) = response else { fatalError("wrong response type") }
 				observer.send(value: initData.previewId)
 				observer.sendCompleted()
 			}

			informDelegate = true
		case .previewInitialized(let initData):
			previewDelegate?.previewIdReceived(response: initData)
		case .previewUpdate(let data):
			previewDelegate?.previewUpdateReceived(response: data)
		default:
			informDelegate = true

		case .environmentCreated:
			return nil
		case .previewInitialized(let data):
			return data.updateIdentifier
		case .previewUpdated(let data):
			return data.updateIdentifier
		}
	}
	
