return fmt.Errorf("Read data = %q; want nothing", data)
		}

		if err := srv.CloseWrite(); err != nil {
			return fmt.Errorf("server CloseWrite: %v", err)
		}

		// Wait for clientCloseWrite to finish, so we know we
		// tested the CloseWrite before we defer the
		// sconn.Close above, which would also cause the
		// client to unblock like CloseWrite.
		<-clientDoneChan
		return nil
	}

	}
	return nil
}

// CloseWrite shuts down the writing side of the TCP connection.
// Most callers should just use Close.
func (c *TCPConn) CloseWrite() error {
	if !c.ok() {
		return syscall.EINVAL
	}
	if err := c.fd.closeWrite(); err != nil {
		return &OpError{Op: "close", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}

	// if needed.
	rstAvoidanceDelay = 1 * time.Nanosecond
}

// SetRSTAvoidanceDelay sets how long we are willing to wait between calling
// CloseWrite on a connection and fully closing the connection.
func SetRSTAvoidanceDelay(t *testing.T, d time.Duration) {
	prevDelay := rstAvoidanceDelay
	t.Cleanup(func() {
		rstAvoidanceDelay = prevDelay
	})

	return alertErr
}

var errEarlyCloseWrite = errors.New("tls: CloseWrite called before handshake complete")

// CloseWrite shuts down the writing side of the connection. It should only be
// called once the handshake has completed and does not call CloseWrite on the
// underlying connection. Most callers should just use [Conn.Close].
func (c *Conn) CloseWrite() error {
	if !c.isHandshakeComplete.Load() {

	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

`TryRead` and `TryWrite` are still available for non-blocking reads and writes.

To signify the end of the stream, close the ring buffer from the writer side with `rb.CloseWriter()`

Either side can use `rb.CloseWithError(err error)` to signal an error and close the ring buffer. 
Any reads or writes will return the error on next call.

		if clientGone {
			// TODO: could we also get into this state if
			// the peer does a half close
			// (e.g. CloseWrite) because they're done
			// sending frames but they're still wanting
			// our open replies?  Investigate.
			// TODO: add CloseWrite to crypto/tls.Conn first
			// so we have a way to test this? I suppose
			// just for testing we could have a non-TLS mode.
			return false

// and always returns nil.
func (r *RingBuffer) CloseWithError(err error) {
	if err == nil {
		err = io.EOF
	}
	r.setErr(err, false)
}

// CloseWriter closes the writer.
// Reads will return any remaining bytes and io.EOF.
func (r *RingBuffer) CloseWriter() {
	r.setErr(io.EOF, false)
}

// Flush waits for the buffer to be empty and fully read.

			}
			if doSleep && writeRng.Intn(10) == 0 {
				time.Sleep(time.Duration(writeRng.Intn(maxSleep)))
			}
		}
		if err := rb.Flush(); err != nil {
			t.Fatalf("flush failed: %v", err)
		}
		rb.CloseWriter()
	}
	wg.Wait()
	if !errors.Is(readErr, io.EOF) {
		t.Fatalf("expect io.EOF but got %v", readErr)
	}
	if readBytes != wroteBytes {
		a, b := readBuf.Bytes(), wroteBuf.Bytes()