protoc从属于不同包的两个proto文件生成golang代码

I have two proto src file, in same folder, let's say:

the 1st one is foo.proto

syntax = "proto3";
package foo;

the second is bar.proto, which need import foo.proto

syntax = "proto3";
import "foo.proto";
package bar;

you can see they have different package name, when I use protoc to generate them one by one, (foo.proto as the 1st of cause), I have two golang file generated, but I have to put them into 2 directory (you can't put different package name file inside same directory, golang )

foo/foo.pb.go
bar/bar.pb.go

but inside bar.pb.go the import are using local import path, which is like

import foo "."

I'm tweeking several options which protoc provided, but didn't make this work, any suggestion?

I believe add option go_package should be the correct solution