import "crypto/tls" import "crypto/x509" import "io/ioutil" cert, err := ioutil.ReadFile("client.crt") if err != nil { panic("Failed to read client certificate") } key, err := ioutil.ReadFile("client.key") if err != nil { panic("Failed to read client key") } certPool := x509.NewCertPool() caCert, err := ioutil.ReadFile("ca.crt") if err != nil { panic("Failed to read CA certificate") } certPool.AppendCertsFromPEM(caCert) tlsConfig := &tls.Config{ Certificates: []tls.Certificate{{ Certificate: [][]byte{cert}, PrivateKey: key, }}, RootCAs: certPool, }In this code snippet, we first load the client certificate and key from files. We then create a certificate pool and load the CA certificate into it. Finally, we create a new `tls.Config` object with the `Certificates` property set to the client certificate and key, and the `RootCAs` property set to the certificate pool containing the CA certificate. With this configuration, a client can use the TLSConfig object to make a secured connection to a server. Therefore, the package library used in this example is the `crypto/tls` package.