5.0.2 无法优雅关机

- [ ] I have searched the [issues](https://github.com/codingapi/tx-lcn/issues) of this repository and believe that this is not a duplicate.

### 1. Bug Description
程序在停机时（`kill PID`），会断开与tm的netty链接，但是链接断开后又会引起重连，因此引发无法优雅关机，最后不得不使用 `kill -9 PID` 的方式来强杀

### 2. Environment:
- JDK version:1.8
- OS:win10
- TX-LCN version:5.0.2
- Others:

### 3. Exception Stacktrace

```
[2019-08-01 10:18:01.480] [nioEventLoopGroup-5-3] [ERROR] io.netty.util.concurrent.DefaultPromise.rejectedExecution [181] - Failed to submit a listener notification task. Event loop shut down?
java.util.concurrent.RejectedExecutionException: event executor terminated
at io.netty.util.concurrent.SingleThreadEventExecutor.reject(SingleThreadEventExecutor.java:842)
at io.netty.util.concurrent.SingleThreadEventExecutor.offerTask(SingleThreadEventExecutor.java:328)
at io.netty.util.concurrent.SingleThreadEventExecutor.addTask(SingleThreadEventExecutor.java:321)
at io.netty.util.concurrent.SingleThreadEventExecutor.execute(SingleThreadEventExecutor.java:765)
at io.netty.util.concurrent.DefaultPromise.safeExecute(DefaultPromise.java:768)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:432)
at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:103)
at io.netty.channel.DefaultChannelPromise.trySuccess(DefaultChannelPromise.java:84)
at io.netty.channel.AbstractChannel$CloseFuture.setClosed(AbstractChannel.java:1148)
at io.netty.channel.AbstractChannel$AbstractUnsafe.register(AbstractChannel.java:490)
at io.netty.channel.SingleThreadEventLoop.register(SingleThreadEventLoop.java:80)
at io.netty.channel.SingleThreadEventLoop.register(SingleThreadEventLoop.java:74)
at io.netty.channel.MultithreadEventLoopGroup.register(MultithreadEventLoopGroup.java:86)
at io.netty.bootstrap.AbstractBootstrap.initAndRegister(AbstractBootstrap.java:333)
at io.netty.bootstrap.Bootstrap.doResolveAndConnect(Bootstrap.java:163)
at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:145)
at com.codingapi.txlcn.txmsg.netty.impl.NettyRpcClientInitializer.connect(NettyRpcClientInitializer.java:109)
at com.codingapi.txlcn.txmsg.netty.impl.NettyRpcClientInitializer.reConnect(NettyRpcClientInitializer.java:76)
at com.codingapi.txlcn.txmsg.netty.handler.NettyClientRetryHandler.channelInactive(NettyClientRetryHandler.java:79)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:224)
at io.netty.channel.ChannelInboundHandlerAdapter.channelInactive(ChannelInboundHandlerAdapter.java:75)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:224)
at io.netty.channel.ChannelInboundHandlerAdapter.channelInactive(ChannelInboundHandlerAdapter.java:75)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:224)
at io.netty.handler.codec.ByteToMessageDecoder.channelInputClosed(ByteToMessageDecoder.java:377)
at io.netty.handler.codec.ByteToMessageDecoder.channelInactive(ByteToMessageDecoder.java:342)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:224)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelInactive(DefaultChannelPipeline.java:1429)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.DefaultChannelPipeline.fireChannelInactive(DefaultChannelPipeline.java:947)
at io.netty.channel.AbstractChannel$AbstractUnsafe$8.run(AbstractChannel.java:822)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasksFrom(SingleThreadEventExecutor.java:380)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:355)
at io.netty.util.concurrent.SingleThreadEventExecutor.confirmShutdown(SingleThreadEventExecutor.java:701)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:456)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(Thread.java:745)

```

### 4. Tour Idea

Start with NettyRpcClientInitializer.connect/reConnect and NettyClientRetryHandler.channelInactive, using the stack trace as the entry point. Trace shutdown handling around the Netty connection and retry path. Done means stopping the process does not trigger another reconnect or produce the rejected-execution error, allowing graceful shutdown.

Escrito por el modelo de indexación a partir del texto del issue.