### Description

The `sendRequest` method is asynchronous and notifies a 
`TransportResponseHandler` when it completes the excecution
(successfully or unsuccessfully). 

When opening the connection we only catch `NodeNotConnectedException`
( https://github.com/elastic/elasticsearch/blob/main/server/src/main/java/org/elasticsearch/transport/TransportService.java#L719 ) which is currently fine as no implementations
throw other type of exception however, it'd be best to catch `Exception` here
so the `handler` gets notified of potential exceptions (as opposed to the caller
having to `try/catch` the call to `sendRequest`)
server/src/main/java/org/elasticsearch/cluster/coordination/CoordinationDiagnosticsService.java
});
    }
    /**
     * This wraps the responseConsumer in a Consumer that will run rescheduleClusterFormationFetchConsumer() after responseConsumer has
     * completed, adding the resulting Cancellable to cancellables.
     * @param masterEligibleNode The node being polled
     * @param responseConsumer The response consumer to be wrapped
     * @param cancellables The Map of Cancellables, one for each node being polled
     * @return
     */
    private Consumer<CoordinationDiagnosticsService.ClusterFormationStateOrException> rescheduleClusterFormationFetchConsumer(
        DiscoveryNode masterEligibleNode,
        Consumer<CoordinationDiagnosticsService.ClusterFormationStateOrException> responseConsumer,
        Map<DiscoveryNode, Scheduler.Cancellable> cancellables
    ) {
        return response -> {
            /*
             * If clusterFormationInfoTasks is null, that means that cancelPollingClusterFormationInfo() has been called, so we don't
             * want to run anything new, and we want to cancel anything that might still be running in our cancellables just to be safe.
             */
            if (clusterFormationInfoTasks != null) {
                /*
                 * If cancellables is not the same as clusterFormationInfoTasks, that means that the current polling track has been
                 * cancelled and a new polling track has been started. So we don't want to run anything new, and we want to cancel
                 * anything that might still be running in our cancellables just to be safe. Note that it is possible for
                 * clusterFormationInfoTasks to be null at this point (since it is assigned in a different thread), so it is important
                 * that we don't call equals on it.
                 */
                if (cancellables.equals(clusterFormationInfoTasks)) {
                    /*