@Override
    public void put(String remoteReceiverWorkName, AbstractWorker instance,
        Class<? extends StreamData> streamDataClass) {
        if (instances.containsKey(remoteReceiverWorkName)) {
            throw new UnexpectedException("Duplicate worker name:" + remoteReceiverWorkName);
        }
        instances.put(remoteReceiverWorkName, new RemoteHandleWorker(instance, streamDataClass));
        LOGGER.debug("Worker {} has been registered as {}", instance.toString(), remoteReceiverWorkName);
    }
Worker Instance Service hosts all remote handler workers with the stream data type.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/worker/WorkerInstancesService.java