How to use the @microsoft/signalr.JsonHubProtocol function in @microsoft/signalr

it("sets the user agent header", async (done) => {
            const hubConnection = getConnectionBuilder(t, TESTHUBENDPOINT_URL)
                .withHubProtocol(new JsonHubProtocol())
                .build();

            try {
                await hubConnection.start();

                // Check to see that the Content-Type header is set the expected value
                const [name, value] = getUserAgentHeader();
                const headerValue = await hubConnection.invoke("GetHeader", name);

                if ((t === HttpTransportType.ServerSentEvents || t === HttpTransportType.WebSockets) && !Platform.isNode) {
                    expect(headerValue).toBeNull();
                } else {
                    expect(headerValue).toEqual(value);
                }

                await hubConnection.stop();

export function eachTransportAndProtocol(action: (transport: HttpTransportType, protocol: IHubProtocol) => void) {
    const protocols: IHubProtocol[] = [new JsonHubProtocol()];
    // Run messagepack tests in Node and Browsers that support binary content (indicated by the presence of responseType property)
    if (typeof XMLHttpRequest === "undefined" || typeof new XMLHttpRequest().responseType === "string") {
        // Because of TypeScript stuff, we can't get "ambient" or "global" declarations to work with the MessagePackHubProtocol module
        // This is only a limitation of the .d.ts file.
        // Everything works fine in the module
        protocols.push(new MessagePackHubProtocol());
    }
    getHttpTransportTypes().forEach((t) => {
        return protocols.forEach((p) => {
            if (t !== HttpTransportType.ServerSentEvents || !(p instanceof MessagePackHubProtocol)) {
                return action(t, p);
            }
        });
    });
}