response: Add Conn and TLS methods

client.go

@@ -164,6 +164,7 @@ func (c *Client) do(ctx context.Context, conn net.Conn, req *Request) (*Response
 	if err != nil {
 		return nil, err
 	}
+	resp.conn = conn
 
 	return resp, nil
 }

response.go

@@ -2,8 +2,10 @@ package gemini
 
 import (
 	"bufio"
+	"crypto/tls"
 	"fmt"
 	"io"
+	"net"
 	"strconv"
 )
 
@@ -36,6 +38,8 @@ type Response struct {
 	// a zero-length body. It is the caller's responsibility to
 	// close Body.
 	Body io.ReadCloser
+
+	conn net.Conn
 }
 
 // ReadResponse reads a Gemini response from the provided io.ReadCloser.
@@ -149,6 +153,21 @@ func (r *Response) Write(w io.Writer) error {
 	return nil
 }
 
+// Conn returns the network connection on which the response was received.
+func (r *Response) Conn() net.Conn {
+	return r.conn
+}
+
+// TLS returns information about the TLS connection on which the
+// response was received.
+func (r *Response) TLS() *tls.ConnectionState {
+	if tlsConn, ok := r.conn.(*tls.Conn); ok {
+		state := tlsConn.ConnectionState()
+		return &state
+	}
+	return nil
+}
+
 // A ResponseWriter interface is used by a Gemini handler to construct
 // a Gemini response.
 //