secure_conn.go
func newSecureConn(ctx context.Context, sk ic.PrivKey, insecure iconn.Conn) (iconn.Conn, error) {

	if insecure == nil {
		return nil, errors.New("insecure is nil")
	}
	if insecure.LocalPeer() == "" {
		return nil, errors.New("insecure.LocalPeer() is nil")
	}
	if sk == nil {
		return nil, errors.New("private key is nil")
	}

	// NewSession performs the secure handshake, which takes multiple RTT
	sessgen := secio.SessionGenerator{LocalID: insecure.LocalPeer(), PrivateKey: sk}
	secure, err := sessgen.NewSession(ctx, insecure)
	if err != nil {
		return nil, err
	}

	conn := &secureConn{
		insecure: insecure,
		secure:   secure,
	}
	return conn, nil
}
func newSecureConn(ctx context.Context, sk ic.PrivKey, insecure iconn.Conn) (iconn.Conn, error) {

	if insecure == nil {
		return nil, errors.New("insecure is nil")
	}
	if insecure.LocalPeer() == "" {
		return nil, errors.New("insecure.LocalPeer() is nil")
	}
	if sk == nil {
		return nil, errors.New("private key is nil")
	}

	// NewSession performs the secure handshake, which takes multiple RTT
	sessgen := secio.SessionGenerator{LocalID: insecure.LocalPeer(), PrivateKey: sk}
	secure, err := sessgen.NewSession(ctx, insecure)
	if err != nil {
		return nil, err
	}

	conn := &secureConn{
		insecure: insecure,
		secure:   secure,
	}
	return conn, nil
}
// newConn constructs a new connection