@Override
                        public void start(final Listener<RespT> responseListener, final Metadata headers) {
                            super.start(new SimpleForwardingClientCallListener<RespT>(responseListener) {

                                @Override
                                public void onClose(final Status status, final Metadata trailers) {
                                    super.onClose(status, trailers);
                                    thatCounter.countDown();
                                }

                            }, headers);
                        }
A testing client interceptor, that allows awaiting the completion of the client call that is otherwise closed
asynchronously.

@return A testing client interceptor bean.
tests/src/test/java/net/devh/boot/grpc/test/config/AwaitableServerClientCallConfiguration.java