In case of Async HTTP, there are 3 different threads involved.

1. Request thread – set MDC here in the request filter.
2. Async thread – copy thread context from request thread to this async thread.
3. Response thread – How do we copy the thread context from the async thread to this thread?

@RestController
public class ServiceChangeStatusPollingApi {

    private final StatusChangePolling statusChangePolling;

    private final Executor taskExecutor;

    @Autowired
    public ServiceChangeStatusPollingApi(StatusChangePolling statusChangePolling,
                                         @Qualifier(TaskConfiguration.ASYNC_EXECUTOR_NAME)
                                         Executor taskExecutor) {
        this.statusChangePolling = statusChangePolling;
        this.taskExecutor = taskExecutor;
    }

    @GetMapping(value = "/status/polling",
            produces = MediaType.APPLICATION_JSON_VALUE)
    @ResponseBody
    public DeferredResult<ServiceDeploymentState> getLatestServiceDeploymentStatus(
            @Parameter(name = "id", description = "ID of the service")
            @RequestParam(name = "id") UUID serviceId,
            @Parameter(name = "previousServiceDeploymentState", description = "Previous known service status to client")
            @RequestParam(name = "previousServiceDeploymentState", required = false)
            ServiceDeploymentState previousServiceDeploymentState
    ) {
        DeferredResult<ServiceDeploymentState> stateDeferredResult = new DeferredResult<>();
        taskExecutor.execute(() ->

                this.statusChangePolling.waitForUsersWithStatus(
                        stateDeferredResult,
                        serviceId,
                        previousServiceDeploymentState));
        return stateDeferredResult;
    }

}

Implemented DeferredResultProcessingInterceptor class but all methods in this class are executed either before the response thread is started or after it is completely executed.