the interface `rocketmq.Producer` can't be implemented outside

[twz915]

type Producer interface {
	Start() error
	Shutdown() error
	SendSync(ctx context.Context, mq ...*primitive.Message) (*primitive.SendResult, error)
	SendAsync(ctx context.Context, mq func(ctx context.Context, result *primitive.SendResult, err error),
		msg ...*primitive.Message) error
	SendOneWay(ctx context.Context, mq ...*primitive.Message) error
	Request(ctx context.Context, ttl time.Duration, msg *primitive.Message) (*primitive.Message, error)
	RequestAsync(ctx context.Context, ttl time.Duration, callback internal.RequestCallback, msg *primitive.Message) error
}

the struct RequestCallback in package internal, so the interface Producer can't be implemented outside

[cserwen]

In what case do we need to implement this interface ourselves?

[twz915]

for example, I want to write a MockProducer to print log only, for test

[oxcafebabe]

using an internal type as an exported function's parameter is really a bad idea