Provide access to context locals.

Motivation:

Expose the list of registered context locals of the vertx instance, so it gives knowledge for interacting with context locals.

src/main/java/io/vertx/core/impl/VertxImpl.java

@@ -137,6 +137,7 @@ private static ThreadFactory virtualThreadFactory() {
   private final Map<ServerID, HttpServerImpl> sharedHttpServers = new HashMap<>();
   private final Map<ServerID, NetServerImpl> sharedNetServers = new HashMap<>();
   private final ContextLocal<?>[] contextLocals;
+  private final List<ContextLocal<?>> contextLocalsList;
   final WorkerPool workerPool;
   final WorkerPool internalWorkerPool;
   final WorkerPool virtualThreaWorkerPool;
@@ -194,6 +195,7 @@ private static ThreadFactory virtualThreadFactory() {
     ThreadFactory virtualThreadFactory = virtualThreadFactory();
 
     contextLocals = LocalSeq.get();
+    contextLocalsList = Collections.unmodifiableList(Arrays.asList(contextLocals));
     closeFuture = new CloseFuture(log);
     maxEventLoopExecTime = maxEventLoopExecuteTime;
     maxEventLoopExecTimeUnit = maxEventLoopExecuteTimeUnit;
@@ -994,6 +996,11 @@ public AddressResolverGroup<InetSocketAddress> nettyAddressResolverGroup() {
     return addressResolver.nettyAddressResolverGroup();
   }
 
+  @Override
+  public List<ContextLocal<?>> contextLocals() {
+    return contextLocalsList;
+  }
+
   @Override
   public FileResolver fileResolver() {
     return fileResolver;

src/main/java/io/vertx/core/impl/VertxInternal.java

@@ -24,6 +24,7 @@
 import io.vertx.core.net.impl.NetServerImpl;
 import io.vertx.core.net.impl.ServerID;
 import io.vertx.core.net.impl.TCPServerBase;
+import io.vertx.core.spi.context.storage.ContextLocal;
 import io.vertx.core.spi.transport.Transport;
 import io.vertx.core.spi.cluster.ClusterManager;
 import io.vertx.core.spi.file.FileResolver;
@@ -33,6 +34,7 @@
 import java.io.File;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
@@ -240,6 +242,11 @@ default <T> Future<T> executeBlockingInternal(Callable<T> blockingCodeHandler, b
    */
   AddressResolverGroup<InetSocketAddress> nettyAddressResolverGroup();
 
+  /**
+   * @return an immutable list of this vertx instance context locals
+   */
+  List<ContextLocal<?>> contextLocals();
+
   BlockedThreadChecker blockedThreadChecker();
 
   CloseFuture closeFuture();

src/main/java/io/vertx/core/impl/VertxWrapper.java

@@ -31,6 +31,7 @@
 import io.vertx.core.net.impl.NetServerImpl;
 import io.vertx.core.net.impl.ServerID;
 import io.vertx.core.net.impl.TCPServerBase;
+import io.vertx.core.spi.context.storage.ContextLocal;
 import io.vertx.core.spi.transport.Transport;
 import io.vertx.core.shareddata.SharedData;
 import io.vertx.core.spi.VerticleFactory;
@@ -42,6 +43,7 @@
 import java.io.File;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.Callable;
@@ -506,6 +508,11 @@ public AddressResolverGroup<InetSocketAddress> nettyAddressResolverGroup() {
     return delegate.nettyAddressResolverGroup();
   }
 
+  @Override
+  public List<ContextLocal<?>> contextLocals() {
+    return delegate.contextLocals();
+  }
+
   @Override
   public BlockedThreadChecker blockedThreadChecker() {
     return delegate.blockedThreadChecker();

src/test/java/io/vertx/core/ContextTest.java

@@ -1253,4 +1253,12 @@ public void testNestedDuplicate() {
     assertEquals("bar", duplicate.getLocal("foo"));
     assertEquals(expected, duplicate.getLocal(contextLocal));
   }
+
+  @Test
+  public void testContextLocals() {
+    List<ContextLocal<?>> locals = ((VertxInternal) vertx).contextLocals();
+    assertSame(ContextInternal.LOCAL_MAP, locals.get(0));
+    assertSame(contextLocal, locals.get(1));
+    assertSame(locals, ((VertxInternal) vertx).contextLocals());
+  }
 }