return h.client.Sum(nil)
	}

	out := make([]byte, 0, md5.Size+sha1.Size)
	out = h.clientMD5.Sum(out)
	return h.client.Sum(out)
}

// clientSum returns the contents of the verify_data member of a client's
// Finished message.
func (h finishedHash) clientSum(masterSecret []byte) []byte {
	out := make([]byte, finishedVerifyLength)
	h.prf(out, masterSecret, clientFinishedLabel, h.Sum())
	return out
}

		return err
	}
	clientFinished, ok := msg.(*finishedMsg)
	if !ok {
		c.sendAlert(alertUnexpectedMessage)
		return unexpectedMessageError(clientFinished, msg)
	}

	verify := hs.finishedHash.clientSum(hs.masterSecret)
	if len(verify) != len(clientFinished.verifyData) ||
		subtle.ConstantTimeCompare(verify, clientFinished.verifyData) != 1 {
		c.sendAlert(alertHandshakeFailure)

	c := hs.c

	if err := c.writeChangeCipherRecord(); err != nil {
		return err
	}

	finished := new(finishedMsg)
	finished.verifyData = hs.finishedHash.clientSum(hs.masterSecret)
	if _, err := hs.c.writeHandshakeRecord(finished, &hs.finishedHash); err != nil {
		return err
	}
	copy(out, finished.verifyData)
	return nil
}

	size := tc.totalSize
	if tc.limitReadSize > 0 {
		if tc.limitReadSize < size {
			size = tc.limitReadSize
		}
	}

	clientUp, serverUp := spawnTestSocketPair(t, tc.upNet)
	defer serverUp.Close()
	cleanup, err := startTestSocketPeer(t, clientUp, "w", tc.chunkSize, size)
	if err != nil {
		t.Fatal(err)
	}
	defer cleanup(t)
	clientDown, serverDown := spawnTestSocketPair(t, tc.downNet)

					if !recvMsg(c, buf[:]) || !sendMsg(c, buf[:]) {
						break
					}
				}
			}(c)
		}
	}()
	clientSem := make(chan bool, numConcurrent)
	for i := 0; i < conns; i++ {
		clientSem <- true
		// Client connection.
		go func() {
			defer func() {
				<-clientSem
			}()
			c, err := Dial("tcp", ln.Addr().String())
			if err != nil {
				b.Log(err)
				return
			}

		}
	}

	checkKeylogLine("client", clientBuf.String())
	checkKeylogLine("server", serverBuf.String())
}

func TestKeyLogTLS13(t *testing.T) {
	var serverBuf, clientBuf bytes.Buffer

	clientConfig := testConfig.Clone()
	clientConfig.KeyLogWriter = &clientBuf

	serverConfig := testConfig.Clone()
	serverConfig.KeyLogWriter = &serverBuf