diff --git a/.gitignore b/.gitignore
index 2739162..3113b5e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 teeworlds_client
 teeworlds
+go-teeworlds-protocol
 
diff --git a/examples/client_verbose/client_verbose.go b/examples/client_verbose/client_verbose.go
index 1376319..893b0a9 100644
--- a/examples/client_verbose/client_verbose.go
+++ b/examples/client_verbose/client_verbose.go
@@ -28,14 +28,20 @@ func main() {
 
 	// read incoming traffic
 	// you can also alter packet here before it will be processed by the internal state machine
-	client.OnPacket(func(packet *protocol7.Packet) {
+	//
+	// return false to drop the packet
+	client.OnPacket(func(packet *protocol7.Packet) bool {
 		fmt.Printf("got packet with %d messages\n", len(packet.Messages))
+		return true
 	})
 
 	// inspect outgoing traffic
 	// you can also alter packet here before it will be sent to the server
-	client.OnSend(func(packet *protocol7.Packet) {
+	//
+	// return false to drop the packet
+	client.OnSend(func(packet *protocol7.Packet) bool {
 		fmt.Printf("sending packet with %d messages\n", len(packet.Messages))
+		return true
 	})
 
 	client.OnChat(func(msg *messages7.SvChat, defaultAction teeworlds7.DefaultAction) {
diff --git a/messages7/cl_say.go b/messages7/cl_say.go
new file mode 100644
index 0000000..42f7e2b
--- /dev/null
+++ b/messages7/cl_say.go
@@ -0,0 +1,57 @@
+package messages7
+
+import (
+	"slices"
+
+	"github.com/teeworlds-go/go-teeworlds-protocol/chunk7"
+	"github.com/teeworlds-go/go-teeworlds-protocol/network7"
+	"github.com/teeworlds-go/go-teeworlds-protocol/packer"
+)
+
+type ClSay struct {
+	ChunkHeader *chunk7.ChunkHeader
+
+	Mode     network7.ChatMode
+	TargetId int
+	Message  string
+}
+
+func (msg *ClSay) MsgId() int {
+	return network7.MsgGameClSay
+}
+
+func (msg *ClSay) MsgType() network7.MsgType {
+	return network7.TypeNet
+}
+
+func (msg *ClSay) System() bool {
+	return false
+}
+
+func (msg *ClSay) Vital() bool {
+	return true
+}
+
+func (msg *ClSay) Pack() []byte {
+	return slices.Concat(
+		packer.PackInt(int(msg.Mode)),
+		packer.PackInt(msg.TargetId),
+		packer.PackStr(msg.Message),
+	)
+}
+
+func (msg *ClSay) Unpack(u *packer.Unpacker) error {
+	msg.Mode = network7.ChatMode(u.GetInt())
+	msg.TargetId = u.GetInt()
+	msg.Message = u.GetString()
+
+	return nil
+}
+
+func (msg *ClSay) Header() *chunk7.ChunkHeader {
+	return msg.ChunkHeader
+}
+
+func (msg *ClSay) SetHeader(header *chunk7.ChunkHeader) {
+	msg.ChunkHeader = header
+}
diff --git a/protocol7/packet.go b/protocol7/packet.go
index f8459c7..d83ce84 100644
--- a/protocol7/packet.go
+++ b/protocol7/packet.go
@@ -285,6 +285,7 @@ func (packet *Packet) Unpack(data []byte) (err error) {
 	return nil
 }
 
+// TODO: return error if maxium packet size is exceeded
 func (packet *Packet) Pack(connection *Session) []byte {
 	payload := []byte{}
 	control := false
@@ -297,6 +298,7 @@ func (packet *Packet) Pack(connection *Session) []byte {
 	}
 
 	packet.Header.NumChunks = len(packet.Messages)
+	packet.Header.Ack = connection.Ack
 
 	if control {
 		packet.Header.Flags = PacketFlags{
diff --git a/protocol7/packet_test.go b/protocol7/packet_test.go
index aa92e0a..15ae55e 100644
--- a/protocol7/packet_test.go
+++ b/protocol7/packet_test.go
@@ -140,6 +140,7 @@ func TestRepackUnknownMessages(t *testing.T) {
 	err := packet.Unpack(dump)
 	require.NoError(t, err)
 
+	conn.Ack = packet.Header.Ack
 	repack := packet.Pack(&conn)
 	require.Equal(t, dump, repack)
 }
diff --git a/protocol7/session.go b/protocol7/session.go
index 38a7b01..a9d48f5 100644
--- a/protocol7/session.go
+++ b/protocol7/session.go
@@ -17,6 +17,7 @@ type Session struct {
 	PeerAck int
 }
 
+// TODO: should this be removed? All of this could be set in Packet.Pack()
 func (connection *Session) BuildResponse() *Packet {
 	return &Packet{
 		Header: PacketHeader{
@@ -26,7 +27,7 @@ func (connection *Session) BuildResponse() *Packet {
 				Resend:      false,
 				Control:     false,
 			},
-			Ack:       connection.Ack,
+			Ack:       0, // will be set in Packet.Pack()
 			NumChunks: 0, // will be set in Packet.Pack()
 			Token:     connection.ServerToken,
 		},
diff --git a/teeworlds7/callbacks.go b/teeworlds7/callbacks.go
index cb971ae..6cc45cc 100644
--- a/teeworlds7/callbacks.go
+++ b/teeworlds7/callbacks.go
@@ -15,8 +15,8 @@ type DefaultAction func()
 // // key is the network7.MessageId
 // UserMsgCallbacks map[int]UserMsgCallback
 type UserMsgCallbacks struct {
-	PacketIn      func(*protocol7.Packet)
-	PacketOut     func(*protocol7.Packet)
+	PacketIn      func(*protocol7.Packet) bool
+	PacketOut     func(*protocol7.Packet) bool
 	MsgUnknown    func(*messages7.Unknown, DefaultAction)
 	InternalError func(error)
 
diff --git a/teeworlds7/packet.go b/teeworlds7/packet.go
index 9c3e76d..fbaae84 100644
--- a/teeworlds7/packet.go
+++ b/teeworlds7/packet.go
@@ -39,7 +39,9 @@ func (client *Client) processMessage(msg messages7.NetMessage, response *protoco
 
 func (client *Client) processPacket(packet *protocol7.Packet) error {
 	if client.Callbacks.PacketIn != nil {
-		client.Callbacks.PacketIn(packet)
+		if client.Callbacks.PacketIn(packet) == false {
+			return nil
+		}
 	}
 
 	response := client.Session.BuildResponse()
diff --git a/teeworlds7/user_actions.go b/teeworlds7/user_actions.go
index 46effc4..cdc4c24 100644
--- a/teeworlds7/user_actions.go
+++ b/teeworlds7/user_actions.go
@@ -1,6 +1,8 @@
 package teeworlds7
 
 import (
+	"fmt"
+
 	"github.com/teeworlds-go/go-teeworlds-protocol/messages7"
 	"github.com/teeworlds-go/go-teeworlds-protocol/network7"
 	"github.com/teeworlds-go/go-teeworlds-protocol/protocol7"
@@ -10,14 +12,77 @@ import (
 // low level access for experts
 // ----------------------------
 
-func (client *Client) SendPacket(packet *protocol7.Packet) {
+// flish()boo  {
+//
+// 	ifhf lenesusue
+// 	packte:=}{}
+// SendPkacte8)
+//
+// }
+//
+// if now > lastsnend d+9191 {
+// 	if !flush() {
+// 		keepalive
+// 	}
+// }A
 
-	// TODO: append queued messages to packet messages here
+func (client *Client) SendPacket(packet *protocol7.Packet) error {
+	if packet.Header.Flags.Resend == false && len(packet.Messages) == 0 && len(client.QueuedMessages) == 0 {
+		return fmt.Errorf("Failed to send packet: payload is empty.")
+	}
+
+	gotNet := false
+	numCtrlMsgs := 0
+
+	for _, msg := range packet.Messages {
+		if msg.MsgType() == network7.TypeControl {
+			numCtrlMsgs++
+		} else if msg.MsgType() == network7.TypeNet {
+			gotNet = true
+		} else {
+			return fmt.Errorf("Failed to send packet: only game, system and control messages are supported.")
+		}
+	}
+
+	if gotNet && numCtrlMsgs > 0 {
+		return fmt.Errorf("Failed to send packet: can not mix control messages with others.")
+	}
+
+	if numCtrlMsgs > 1 {
+		// TODO: should this automatically split it up into multiple packets?
+		return fmt.Errorf("Failed to send packet: can only send one control message at a time.")
+	}
+
+	// If the user queued a game message and then sends a control message
+	// before the queue got processed we send two packets in the correct order
+	// For example in this case:
+	//
+	// client.SendChat("bye") // queue game chunk
+	// client.Disconnect() // SendPacket(ctrl) -> first flush out the game chunk packet then send the control packet
+	//
+	if numCtrlMsgs > 0 && len(client.QueuedMessages) > 0 {
+		// TODO: we could apply compression here
+		// flushPacket.Header.Flags.Compression = true
+
+		flushPacket := client.Session.BuildResponse()
+		client.SendPacket(flushPacket)
+	}
+
+	for _, queuedChunk := range client.QueuedMessages {
+		// TODO: check if we exceed packet size and only put in as many chunks as we can
+		//       also use a more performant queue implementation then if we unshift it partially
+		//       popping of one element from the queue should not reallocate the entire queued messages slice
+		packet.Messages = append(packet.Messages, queuedChunk)
+	}
+	client.QueuedMessages = nil
 
 	if client.Callbacks.PacketOut != nil {
-		client.Callbacks.PacketOut(packet)
+		if client.Callbacks.PacketOut(packet) == false {
+			return nil
+		}
 	}
 	client.Conn.Write(packet.Pack(&client.Session))
+	return nil
 }
 
 // WARNING! this is does not send chat messages
@@ -25,7 +90,18 @@ func (client *Client) SendPacket(packet *protocol7.Packet) {
 //
 // if you want to send a chat message use SendChat()
 func (client *Client) SendMessage(msg messages7.NetMessage) {
-	// TODO: set vital header and stuff
+	if msg.MsgType() == network7.TypeControl {
+		packet := client.Session.BuildResponse()
+		packet.Header.Flags.Control = true
+		packet.Messages = append(packet.Messages, msg)
+		client.SendPacket(packet)
+		return
+	}
+	if msg.MsgType() == network7.TypeConnless {
+		// TODO: connless
+		panic("connless messages are not supported yet")
+	}
+
 	client.QueuedMessages = append(client.QueuedMessages, msg)
 }
 
@@ -37,7 +113,7 @@ func (client *Client) SendMessage(msg messages7.NetMessage) {
 // see also SendChatTeam()
 func (client *Client) SendChat(msg string) {
 	client.SendMessage(
-		&messages7.SvChat{
+		&messages7.ClSay{
 			Mode:     network7.ChatAll,
 			Message:  msg,
 			TargetId: -1,
@@ -49,7 +125,7 @@ func (client *Client) SendChat(msg string) {
 // see also SendChat()
 func (client *Client) SendChatTeam(msg string) {
 	client.SendMessage(
-		&messages7.SvChat{
+		&messages7.ClSay{
 			Mode:     network7.ChatTeam,
 			Message:  msg,
 			TargetId: -1,
@@ -61,7 +137,7 @@ func (client *Client) SendChatTeam(msg string) {
 // see also SendChatTeam()
 func (client *Client) SendWhisper(targetId int, msg string) {
 	client.SendMessage(
-		&messages7.SvChat{
+		&messages7.ClSay{
 			Mode:     network7.ChatWhisper,
 			Message:  msg,
 			TargetId: targetId,
diff --git a/teeworlds7/user_hooks.go b/teeworlds7/user_hooks.go
index 8176eb6..0437fed 100644
--- a/teeworlds7/user_hooks.go
+++ b/teeworlds7/user_hooks.go
@@ -16,13 +16,17 @@ func (client *Client) OnError(callback func(err error)) {
 
 // inspect outgoing traffic
 // and alter it before it gets sent to the server
-func (client *Client) OnSend(callback func(packet *protocol7.Packet)) {
+//
+// return false to drop the packet
+func (client *Client) OnSend(callback func(packet *protocol7.Packet) bool) {
 	client.Callbacks.PacketOut = callback
 }
 
 // read incoming traffic
 // and alter it before it hits the internal state machine
-func (client *Client) OnPacket(callback func(packet *protocol7.Packet)) {
+//
+// return false to drop the packet
+func (client *Client) OnPacket(callback func(packet *protocol7.Packet) bool) {
 	client.Callbacks.PacketIn = callback
 }