- [x] I have searched the [issues](https://github.com/apache/dubbo/issues) of this repository and believe that this is not a duplicate.
- [x] I have checked the [FAQ](https://github.com/apache/dubbo/blob/master/FAQ.md) of this repository and believe that this is not a duplicate.

### Environment

* Dubbo version: 2.7.6
* Operating System version: CentOS-7
* Java version: 1.8.0_275

### Steps to reproduce this issue

dobbo use netty to listen as a server .  and use this class SslConfig.java  and netty4/SslContexts.java to use ssl cert file .
this class always open file .
by netty's source :  PemReader and SslContextBuilder they not close this InputStream yet .and netty expect user close the InputStream if the InputStream is open by user.

https://github.com/netty/netty/issues/10974
https://github.com/netty/netty/pull/10976

but it seems dobbo not close it ?

![image](https://user-images.githubusercontent.com/5086059/106403950-e61ef980-646b-11eb-9d8d-2c21550e4954.png)

![image](https://user-images.githubusercontent.com/5086059/106403961-ecad7100-646b-11eb-929e-5ec79837886d.png)

Pls. provide [GitHub address] to reproduce this issue.

### Expected Result

InputStream maybe need close immediately?

### Actual Result

InputStream seems leak.


}
        int maxCalls = url.getParameter(MAX_CONCURRENT_CALLS_PER_CONNECTION, url.getParameter(EXECUTES_KEY, 0));
        if (maxCalls > 0) {
            builder.maxConcurrentCallsPerConnection(maxCalls);
        }
        
        List<ServerInterceptor> serverInterceptors = url.getOrDefaultFrameworkModel().getExtensionLoader(ServerInterceptor.class)
                .getActivateExtension(url, SERVER_INTERCEPTORS, PROVIDER_SIDE);
        for (ServerInterceptor serverInterceptor : serverInterceptors) {
            builder.intercept(serverInterceptor);
        }
        
        List<ServerTransportFilter> transportFilters = url.getOrDefaultFrameworkModel().getExtensionLoader(ServerTransportFilter.class)
                .getActivateExtension(url, TRANSPORT_FILTERS, PROVIDER_SIDE);
        for (ServerTransportFilter transportFilter : transportFilters) {
            builder.addTransportFilter(transportFilter.grpcTransportFilter());
        }
        String thread = url.getParameter(EXECUTOR, url.getParameter(DISPATCHER_KEY));
        if ("direct".equals(thread)) {
            builder.directExecutor();
        } else {
            builder.executor(url.getOrDefaultFrameworkModel().getExtensionLoader(ThreadPool.class).getAdaptiveExtension().getExecutor(url));
        }
        
        return getConfigurator()
                .map(configurator -> configurator.configureServerBuilder(builder, url))
                .orElse(builder);
    }
    static ManagedChannel buildManagedChannel(URL url) {
        NettyChannelBuilder builder = NettyChannelBuilder.forAddress(url.getHost(), url.getPort());