@Override
    public <RequestT, ResponseT> ClientCall<RequestT, ResponseT> newCall(MethodDescriptor<RequestT, ResponseT> methodDescriptor,
                                                                         CallOptions callOptions) {
        return grpcChannel.newCall(methodDescriptor, callOptions);
    }
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