}

// ReadFrom is here to optimize copying from an [*os.File] regular file
// to a [*net.TCPConn] with sendfile, or from a supported src type such
// as a *net.TCPConn on Linux with splice.
func (w *response) ReadFrom(src io.Reader) (n int64, err error) {
	buf := getCopyBuf()
	defer putCopyBuf(buf)

	// Our underlying w.conn.rwc is usually a *TCPConn (with its
	// own ReadFrom method). If not, just fall back to the normal
	// copy method.

					conn, err := d.DialContext(ctx, network, addr)
					if err != nil {
						return nil, err
					}

					tcpConn, ok := conn.(*net.TCPConn)
					if !ok {
						return nil, fmt.Errorf("%s/%s does not provide a *net.TCPConn", network, addr)
					}

					tConn.TCPConn = tcpConn
					return tConn, nil
				}
			}

			cst := newClientServerTest(
				t,
				mode,

			if err != nil {
				t.Errorf("Hijack in Handler: %v", err)
				return
			}
			if _, ok := c.(*net.TCPConn); !ok {
				// Verify it's not wrapped in some type.
				// Not strictly a go1 compat issue, but in practice it probably is.
				t.Errorf("type of hijacked conn is %T; want *net.TCPConn", c)
			}
			fmt.Fprintf(c, "HTTP/1.0 200 OK\r\nX-Addr: %v\r\nContent-Length: 0\r\n\r\n", r.RemoteAddr)
			c.Close()