Similarly to https://github.com/elastic/elasticsearch/pull/97873 but for request handlers: let's stop passing around strings and looking these things up by name on each request when we could just pass around the `Executor` itself.
server/src/main/java/org/elasticsearch/action/support/broadcast/unpromotable/TransportBroadcastUnpromotableAction.java
* 2.0 and the Server Side Public License, v 1; you may not use this file except
 * in compliance with, at your election, the Elastic License 2.0 or the Server
 * Side Public License, v 1.
 */
package org.elasticsearch.action.support.broadcast.unpromotable;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.action.ActionListenerResponseHandler;
import org.elasticsearch.action.ActionResponse;
import org.elasticsearch.action.support.ActionFilters;
import org.elasticsearch.action.support.ChannelActionListener;
import org.elasticsearch.action.support.HandledTransportAction;
import org.elasticsearch.action.support.RefCountingListener;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.action.shard.ShardStateAction;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.service.ClusterService;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.Writeable;
import org.elasticsearch.core.Strings;
import org.elasticsearch.tasks.Task;
import org.elasticsearch.transport.TransportChannel;
import org.elasticsearch.transport.TransportRequestHandler;
import org.elasticsearch.transport.TransportRequestOptions;
import org.elasticsearch.transport.TransportService;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Executor;
public abstract class TransportBroadcastUnpromotableAction<Request extends BroadcastUnpromotableRequest, Response extends ActionResponse>