HttpContext.Request 在 .NET 7 Isolated 中不起作用

Question

public static HttpRequest CreateHttpRequestFromBody(string body)
{           
    var context = new DefaultHttpContext();
    var stream = new MemoryStream(Encoding.UTF8.GetBytes(body));
    var request = context.Request;
    request.Body = stream;
    request.ContentLength = stream.Length;
    return request;
}

谁能告诉我 .NET 7 Isolated 中的替代方法是什么 我想在 .NET 7 中隔离 Body 和 ContentLenth