报错信息：
grpc maven 编译 Error: java:: Tried to write the same file twice.
PROTOC FAILED: Account.proto:90:5: “Ret” is not defined.

引入其他proto时：

• 同目录使用 import “Enums.proto”;
• package要和被引入的相同
• 某个proto引入Enums.proto

syntax = "proto3";
import "Enums.proto";
option java_multiple_files = true;
option java_package = "com.company.strategy";
option java_outer_classname = "Strategy";
option objc_class_prefix = "company";
package strategy;

• Enums.proto

syntax = "proto3";
option java_multiple_files = true;
option java_package = "com.company.quantitative_trading_account";
option java_outer_classname = "Enums";
option objc_class_prefix = "company";
package strategy;

enum SubscribeType{
    //占位
    SubscribeType_ZERO = 0;
    //订阅
    SUBSCRIBE = 1;
    //取消订阅
    UNSUBSCRIBE = 2;
}
....

保持package相同，以及没有重复两个里头都写有相同message/enum即可编译通过