### Feature and motivation

Be able to link custom OpenTelemetry tracing with the default Selenium grid tracing. See for e.g. https://github.com/llatinov/selenium-observability-java/blob/324b500316be34f5f1426720353d0c4e2e8b5a89/selenium-tests/src/main/java/com/automationrhapsody/observability/TracingWebDriver.java#L81 
It will be useful if I am able to pass my Span as a parent span of Selenium's RemoteWebDriver tracing, so I can trace my actions with corresponding grid actions.

### Usage example

Implement a custom tracing that monitors the tests. It will be of great help to be able to make the default server/grid tracing a child of the custom tracking. In this case, users can monitor how a click of a button in their tests links to grid performance.
}
  @Test
  public void nestingSpansFromDifferentThreadsIsFineToo() throws ExecutionException, InterruptedException {
    List<SpanData> allSpans = new ArrayList<>();
    Tracer tracer = createTracer(allSpans);
    try (Span parent = tracer.getCurrentContext().createSpan("parent")) {
      Future<?> future = Executors.newSingleThreadExecutor().submit(() -> {
        try (Span child = parent.createSpan("child")) {
          child.setAttribute("cheese", "gruyere");
        }
      });
      future.get();
    }
    SpanData parent = allSpans.stream().filter(data -> data.getName().equals("parent"))
        .findFirst().orElseThrow(NoSuchElementException::new);
    SpanData child = allSpans.stream().filter(data -> data.getName().equals("child"))
        .findFirst().orElseThrow(NoSuchElementException::new);
    assertThat(child.getParentSpanId()).isEqualTo(parent.getSpanId());
  }
  @Test
  public void currentSpanIsKeptOnTracerCorrectlyWithinSameThread() {
    List<SpanData> allSpans = new ArrayList<>();
    Tracer tracer = createTracer(allSpans);
    try (Span parent = tracer.getCurrentContext().createSpan("parent")) {
      assertThat(parent.getId()).isEqualTo(tracer.getCurrentContext().getId());
      try (Span child = parent.createSpan("child")) {
        assertThat(child.getId()).isEqualTo(tracer.getCurrentContext().getId());
      }
      assertThat(parent.getId()).isEqualTo(tracer.getCurrentContext().getId());
    }