[Bug] Biz Exceptions occured in EventMesh cause connection close of client

[lrhkobe]

Bug Report

Describe the bug

When exception occured in the method of channelRead0, it will be thrown, and handled by the method 'exceptionCaught' in the class of EventMeshTcpExceptionHandler .

public class EventMeshTcpMessageDispatcher extends SimpleChannelInboundHandler<Package> {

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, Package pkg) throws Exception { 
        try {
            ...

            dispatch(ctx, pkg, startTime, cmd);
        } catch (Exception e) {
            logger.error("exception occurred while pkg|cmd={}|pkg={}|errMsg={}", cmd, pkg, e);
            //throw new RuntimeException(e);
            throw e;
        }
    }
}

When EventMesh caught the exception, it will send goodbye instruction to the client, that means the biz exception caused the connection close of client. It seems unreasonable.

public class EventMeshTcpExceptionHandler extends ChannelDuplexHandler {

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        Session session = eventMeshTCPServer.getClientSessionGroupMapping().getSession(ctx);
        UserAgent client = session == null ? null : session.getClient();
        logger.error("exceptionCaught, push goodbye to client|user={},errMsg={}", client, cause.fillInStackTrace());
        String errMsg;
        if (cause.toString().contains("value not one of declared Enum instance names")) {
            errMsg = "Unknown Command type";
        } else {
            errMsg = cause.toString();
        }

        if (session != null) {
            EventMeshTcp2Client.goodBye2Client(eventMeshTCPServer, session, errMsg, OPStatus.FAIL.getCode(), eventMeshTCPServer.getClientSessionGroupMapping());
        } else {
            EventMeshTcp2Client.goodBye2Client(ctx, errMsg, eventMeshTCPServer.getClientSessionGroupMapping(), eventMeshTCPServer.getEventMeshTcpMonitor());
        }
    }
}