How to Preserve Span Attributes in OpenTelemetry without Overwriting

    with using_metadata(metadata={'foo': 'bar'}):

        ...

        with self._tracer.start_as_current_span(
            func.__class__.__name__,
            openinference_span_kind="tool",
        ) as span:
            ...

            span.set_input(func.model_dump()) # func is a pydantic BaseModel)
            output = func.call(func_input)

            span.set_output(output.response) # textual response to be fed back to LLM

            # Save additional output as metadata
            span.set_attribute(
                key=semcov_trace.SpanAttributes.METADATA,
                value=json.dumps({'x': output.metadata})
                ),
            )