WebSocket Support/Examples

As JSR 375 was supposed to cross the JEE spec, I see no mention anywhere of WebSocket support. One of the pain points of using JSR 356 is performing security checks such as `#isUserInRole` after the connection has been established as it only currently appears in `javax.websocket.server.HandshakeRequest`.

The JSR 356 spec. states:

> Websocket endpoints running in the Java EE platform must have full dependency injection support as described in the CDI specification.

Therefore, it should be possible to inject the `javax.security.SecurityContext` into a WebSocket `javax.websocket.Endpoint`, however I see no documentation or examples supporting this. Is this a valid assumption? I appreciate the horse may have already bolted, but I'd be surprised if this hasn't been discussed already.

Start by reviewing the JSR 356 and JSR 375 references in the issue and searching the repository for WebSocket, Endpoint, and SecurityContext documentation or examples. Determine whether the stated injection assumption is supported; done means the support status is established and the relevant guidance or example is documented.

Written by the indexing model from the issue text.