如何将lua变量返回到nginx变量中

http {
    server {
        location /test {
            default_type 'text/plain';

            # 设置内容由 Lua 脚本生成
            content_by_lua_block {
                ngx.var.my_var = "Hello from Lua"  -- 设置 Nginx 变量
                ngx.say("This is a response from Lua!")
            }

            # 使用 Lua 设置的变量
            add_header X-My-Var $my_var;
        }
    }
}

http {
    server {
        location /demo {
            default_type 'text/plain';

            set $dynamic_header '';

            content_by_lua_block {
                local response_condition = 1  -- 假设这是根据某些逻辑得到的结果
                if response_condition == 1 then
                    ngx.var.dynamic_header = "Value1"
                else
                    ngx.var.dynamic_header = "Value2"
                end
                ngx.say("Check the response header!")
            }

            add_header X-Dynamic $dynamic_header;
        }
    }
}