better node removal

packet.go

@@ -3,6 +3,7 @@ package main
 import (
 	"encoding/binary"
 	"encoding/json"
+	"fmt"
 	"io"
 )
 
@@ -30,6 +31,9 @@ func SendCartPacket(conn io.Writer, id CartId, messageType uint16, datafn func(w
 	if err != nil {
 		return err
 	}
+	if conn == nil {
+		return fmt.Errorf("no connection to send to")
+	}
 	binary.Write(conn, binary.LittleEndian, CartPacket{
 		Version:     2,
 		MessageType: messageType,