Revert "Revert "优化服务退出流程，增加中间件文档""

This reverts commit 64ed43b7ca.

server/internal/library/network/tcp/server.go

@@ -294,6 +294,11 @@ func (server *Server) Close() {
 	server.wgLn.Wait()
 }
 
+// IsClose 服务是否关闭
+func (server *Server) IsClose() bool {
+	return server.closeFlag
+}
+
 // Write 向指定客户端发送消息
 func (server *Server) Write(conn *gtcp.Conn, data interface{}) (err error) {
 	if server.closeFlag {