conn, err := net.Dial("tcp", ts.Listener.Addr().String())
	if err != nil {
		t.Fatalf("Dial: %v", err)
	}
	err = conn.(*net.TCPConn).CloseWrite()
	if err != nil {
		t.Fatalf("CloseWrite: %v", err)
	}

	bs, err := io.ReadAll(conn)
	if err != nil {
		t.Errorf("ReadAll: %v", err)
	}
	got := string(bs)
	if got != "" {

//
// TODO(bcmills): This should arguably be a server configuration parameter,
// not a hard-coded value.
var rstAvoidanceDelay = 500 * time.Millisecond

type closeWriter interface {
	CloseWrite() error
}

var _ closeWriter = (*net.TCPConn)(nil)

// closeWriteAndWait flushes any outstanding data and sends a FIN packet (if
// client is connected via TCP), signaling that we're done. We then