Should McpTransportContextExtractor contain default methods for protocol version, lastEventId and sessionId

I am defining my McpTransportContextExtractor implementation as:

@Internal
@Singleton
class DefaultMcpTransportContextExtractor implements McpTransportContextExtractor<HttpRequest<?>> {
    public static final String HTTP_HEADER_MCP_PROTOCOL_VERSION = "MCP-Protocol-Version";
    public static final String DEFAULT_PROTOCOL_VERSION = "2025-03-26";
    public static final String HTTP_HEADER_MCP_SESSION_ID = "Mcp-Session-Id";
    public static final String HTTP_HEADER_DEFAULT_LAST_EVENT_ID = "Last-Event-ID";

    @Override
    public McpTransportContext extract(HttpRequest<?> request, McpTransportContext transportContext) {
        transportContext.put(HTTP_HEADER_MCP_PROTOCOL_VERSION,
            request.getHeaders().get(HTTP_HEADER_MCP_PROTOCOL_VERSION, String.class)
                .orElse(DEFAULT_PROTOCOL_VERSION));
        request.getHeaders().get(HTTP_HEADER_MCP_SESSION_ID, String.class)
            .ifPresent(v -> transportContext.put(HTTP_HEADER_MCP_SESSION_ID, v));
        request.getHeaders().get(HTTP_HEADER_DEFAULT_LAST_EVENT_ID, String.class)
            .ifPresent(v -> transportContext.put(HTTP_HEADER_DEFAULT_LAST_EVENT_ID, v));
        return transportContext;
    }
}

But given that the specification defines session id, last event and protocol version. I think it would be good if the McpTransportContextExtractor contained default methods:

default String getSessionId() {
   return null;
}

default String getLastEventId() {
   return null;
}

default String getProtocolVersion() {
   return "2025-03-26";
}

I can submit a PR if you think it is a good idea. With this change the TransportContext will have a clear API for those spec defined concepts.

Localisez McpTransportContextExtractor et examinez ses implémentations existantes ainsi que l’utilisation de McpTransportContext. Vérifiez si les accesseurs par défaut pour la version du protocole, l’ID de session et l’ID du dernier événement correspondent à l’API actuelle et aux concepts du protocole ; le travail est terminé lorsque l’interface expose une API cohérente et compatible.