public static WebSocketUpgradeResult ofFailure(HttpResponse fallbackResponse) {
        requireNonNull(fallbackResponse, "failureResponse");
        return new WebSocketUpgradeResult(fallbackResponse);
    }
Returns a failed {@link WebSocketUpgradeResult} with the fallback {@link HttpResponse}.
core/src/main/java/com/linecorp/armeria/server/websocket/WebSocketUpgradeResult.java