Documentation Helidon SE: Can not resolve method asChildOf(Optional<SpanContext>)

[tvallin]

The Helidon SE Tracing Guide asks to update GreetResource with this code:

import io.opentracing.Span; // (1)
...
    private void getDefaultMessageHandler(ServerRequest request,
                                   ServerResponse response) {

        Span span = request.tracer()  // (2)
            .buildSpan("getDefaultMessageHandler")  // (3)
            .asChildOf(request.spanContext())  // (4)
            .start(); // (5)

        try {
            sendResponse(response, "World");
        } finally {
            span.finish();  // (6)
        }
    }

The .asChildOf(request.spanContext()) throw an Exception that the method can not be resolved.
Helidon version 2.1.0/2.1.1-SNAPSHOT. I faced the issue with both.

Note:
To fix this I modified it like this .asChildOf(request.spanContext().get()), then continue the guide and it worked perfectly for me.