@Override
    public ManagedChannel shutdown() {
        if (referenceCount.decrementAndGet() <= 0) {
            return grpcChannel.shutdown();
        }
        return grpcChannel;
    }
The reference count of current ExchangeClient, connection will be closed if all invokers destroyed.
remoting/remoting-triple/src/main/java/com/alipay/sofa/rpc/transport/triple/ReferenceCountManagedChannel.java