### 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.
import org.openqa.selenium.remote.http.Routable;
import org.openqa.selenium.remote.http.Route;
import org.openqa.selenium.remote.tracing.EventAttribute;
import org.openqa.selenium.remote.tracing.EventAttributeValue;
import org.openqa.selenium.remote.tracing.HttpTracing;
import org.openqa.selenium.remote.tracing.Span;
import org.openqa.selenium.remote.tracing.Status;
import org.openqa.selenium.remote.tracing.Tracer;
import org.openqa.selenium.testing.UnitTests;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.stream.Collectors;
import static org.assertj.core.api.Assertions.assertThat;
import static org.openqa.selenium.remote.http.HttpMethod.GET;
import static org.openqa.selenium.remote.tracing.HttpTracing.newSpanAsChildOf;
@Category(UnitTests.class)
public class TracerTest {
  @Before