Go版本Compose

写了个Go版本的，有时间再补充。

type Compose struct {
    handlers []func(ctx context.Context, next func())
    ctx      context.Context
}

func (c *Compose) New(handlers []func(ctx context.Context, next func())) *Compose {
    c.handlers = handlers
    return c
}

func (c *Compose) Do(ctx context.Context) {
    c.dispatch(0)
}

func (c *Compose) dispatch(i int) {
    c.handlers[i](c.ctx, func() {
        c.dispatch(i+1)
    })
}