Switch-case fall through in ChannelEventRunnable

[biyuhao]

• I have searched the issues of this repository and believe that this is not a duplicate.
• I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

• Dubbo version: latest master branch
• Operating System version: macos
• Java version: 1.8

Description

in ChannelEventRunnable#run there is a switch-case fall through which is introduced in b3e91fa .
I believe this is a little mistake, and UT is not necessary.

As shown below, there is no break statement after SENT, I will send a pr later.

...
            case DISCONNECTED:
                try {
                    handler.disconnected(channel);
                } catch (Exception e) {
                    logger.warn("ChannelEventRunnable handle " + state + " operation error, channel is " + channel, e);
                }
                break;
            case SENT:
                try {
                    handler.sent(channel, message);
                } catch (Exception e) {
                    logger.warn("ChannelEventRunnable handle " + state + " operation error, channel is " + channel
                            + ", message is " + message, e);
                }
               // no break statement here!
            case CAUGHT:
                try {
                    handler.caught(channel, exception);
                } catch (Exception e) {
                    logger.warn("ChannelEventRunnable handle " + state + " operation error, channel is " + channel
                            + ", message is: " + message + ", exception is " + exception, e);
                }
                break;
            default:
                logger.warn("unknown state: " + state + ", message is " + message);
            }