/** SessionContext interface. It's an entrypoint for all non-tabular information. */
public class SessionContext {
    /** @return Client attributes set for current thread. */
    public static @Nullable Map<String, String> getClientAttributes();
 }
 
/** Example, use it in QuerySqlFunction. */
public static class UserDefinedFunctions {
    /** @return Session ID, client attribute. */
    @QuerySqlFunction
    public static String sessionId() {
        Map<String, String> clnAttrs = SessionContext.getClientAttributes();
 
        return clnAttrs == null ? null : clnInfo.getProperty(SESSION_ID);
    }
}