@Override
    public void onError(final Throwable t) {
        for (StreamObserver<T> observer : observers) {
            try {
                observer.onError(t);
            } catch (Exception exception) {
                LOG.error("Exception in composite onError, moving on", exception);
            }
        }
    }
CompositeStreamObserver of.

@param observers        observers
@param completeObserver completeObserver
@param <T>              t
@return CompositeStreamObserver compositeStreamObserver
shenyu-plugin/shenyu-plugin-proxy/shenyu-plugin-rpc/shenyu-plugin-grpc/src/main/java/org/apache/shenyu/plugin/grpc/proto/CompositeStreamObserver.java