我有一个用spring引导和google应用引擎构建的应用程序。我尝试通过遵循本教程实现服务器发送事件。当我构建并尝试访问创建sse发射器的端点时,我会得到以下错误
java.lang.IllegalStateException: Async support must be enabled on a servlet and for all filters involved in async request processing. This is done in Java code using the Servlet API or by adding "<async-supp