private boolean compare(List<RemoteInstance> remoteInstances) {
        if (usingClients.size() == remoteInstances.size()) {
            for (int i = 0; i < usingClients.size(); i++) {
                if (!usingClients.get(i).getAddress().equals(remoteInstances.get(i).getAddress())) {
                    return false;
                }
            }
            return true;
        } else {
            return false;
        }
    }
Compare clients between exist clients and remote instance collection. Move the clients into new client collection
which are alive to avoid create a new channel. Shutdown the clients which could not find in cluster config.
<p>
Create a gRPC client for remote instance except for self-instance.

@param remoteInstances Remote instance collection by query cluster config.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/remote/client/RemoteClientManager.java