How to get credentials when integrating clash in go code

[xzycn]

Hi, I'm integrating clash in my project.
I cannot get credentials(user,password) from context, the example code is here:

for c := range in {
               // want to get credentials here.
		conn := c
		metadata := conn.Metadata()
		fmt.Printf("request incoming from %s to %s\n", metadata.SourceAddress(), metadata.RemoteAddress())
		go func () {
			remote, err := direct.DialContext(context.Background(), metadata)
			if err != nil {
				fmt.Printf("dial error: %s\n", err.Error())
				return
			}
			relay(remote, conn.Conn())
		}()
}

How can we get credentials here?