Sending a custom plugin message from BungeeCord

public class ExampleMain extends Plugin
{

    @Override
    public void onEnable()
    {
        getProxy().registerChannel( "my:channel" );
        getLogger().info( "Plugin enabled!" );
    }

    @Override
    public void onDisable()
    {
        getLogger().info( "Plugin disabled!" );
    }
}

public void sendCustomData(ProxiedPlayer player, String data1, int data2)
{
    Collection<ProxiedPlayer> networkPlayers = ProxyServer.getInstance().getPlayers();
    // perform a check to see if globally are no players
    if ( networkPlayers == null || networkPlayers.isEmpty()) return;

    ByteArrayDataOutput out = ByteStreams.newDataOutput();
    out.writeUTF( "MySubChannel" ); // the channel could be whatever you want
    out.writeUTF( data1 ); // this data could be whatever you want
    out.writeInt( data2 ); // this data could be whatever you want
 
    // we send the data to the server
    // using ServerInfo the packet is being queued if there are no players in the server
    // using only the server to send data the packet will be lost if no players are in it
    player.getServer().getInfo().sendData( "my:channel", out.toByteArray() );
}

public class PluginMessageReceiver implements Listener
{

    @EventHandler
    public void on(PluginMessageEvent event)
    {
        if ( !event.getTag().equalsIgnoreCase("my:channel")) return;

        ByteArrayDataInput in = ByteStreams.newDataInput( event.getData() );
        String subChannel = in.readUTF();
        if ( subChannel.equalsIgnoreCase( "OtherSubchannel" ) )
        {
            // the receiver is a ProxiedPlayer when a server talks to the proxy
            if ( event.getReceiver() instanceof ProxiedPlayer )
            {
                ProxiedPlayer receiver = (ProxiedPlayer) event.getReceiver();
                // do things
            }
            // the receiver is a server when the proxy talks to a server
            if ( event.getReceiver() instanceof Server )
            {
                Server receiver = (Server) event.getReceiver();
                // do things
            }
        }
    }
}

public class ExampleMainDriver extends JavaPlugin implements PluginMessageListener
{

    @Override
    public void onEnable()
    {
        checkIfBungee();
        if ( !getServer().getPluginManager().isPluginEnabled( this ) )
        {
            return;
        }
        getServer().getMessenger().registerIncomingPluginChannel( this, "my:channel", this ); // we register the incoming channel
        // you can register outgoing channel if you want to send messages to the proxy
        // getServer().getMessenger().registerOutgoingPluginChannel( this, "my:channel" );
        getLogger().info( "<pluginName> driver enabled successfully." );
    }

    @Override
    public void onDisable()
    {
        getLogger().info( "<pluginName> driver was disabled!" );
    }

    @Override
    public void onPluginMessageReceived(String channel, Player player, byte[] bytes)
    {
        if ( !channel.equalsIgnoreCase( "my:channel" ) )
        {
            return;
        }
        ByteArrayDataInput in = ByteStreams.newDataInput( bytes );
        String subChannel = in.readUTF();
        if ( subChannel.equalsIgnoreCase( "MySubChannel" ) )
        {
            String data1 = in.readUTF();
            int data2 = in.readInt();

            // do things with the data
        }
    }

    // we check like that if the specified server is BungeeCord.
    private void checkIfBungee()
    {
        // we check if the server is Spigot/Paper (because of the spigot.yml file)
        if ( !getServer().getVersion().contains( "Spigot" ) && !getServer().getVersion().contains( "Paper" ) )
        {
            getLogger().severe( "You probably run CraftBukkit... Please update atleast to spigot for this to work..." );
            getLogger().severe( "Plugin disabled!" );
            getServer().getPluginManager().disablePlugin( this );
            return;
        }
        if ( getServer().spigot().getConfig().getConfigurationSection("settings").getBoolean( "settings.bungeecord" ) )
        {
            getLogger().severe( "This server is not BungeeCord." );
            getLogger().severe( "If the server is already hooked to BungeeCord, please enable it into your spigot.yml aswell." );
            getLogger().severe( "Plugin disabled!" );
            getServer().getPluginManager().disablePlugin( this );
        }
    }
}