Make sure you're doing the following

• [ x ] You're using the latest build for your server version
• [ x ] This isn't an issue caused by another plugin
• [ x ] You've checked for duplicate issues
• [ x ] You didn't use /reload

Describe the question
I face index out of bounds question in writing a packet.I create a PacketContainer with CUSTOM_PAYLOAD,when I start to write something in it, the error happend.The code are follow:
`PacketContainer packet = ProtocolLibrary.getProtocolManager().createPacket(PacketType.Play.Server.CUSTOM_PAYLOAD);

    plugin.getLogger().info("Sending dialog packet to player: " + player.getName());
    plugin.getLogger().info(String.valueOf(packet.getStrings().size()));
    packet.getStrings().write(0, "qiuling:dialog_packet");
    plugin.getLogger().info("Sending dialog packet to player: " + player.getName());`

and the error logger like this:
com.comphenix.protocol.reflect.FieldAccessException: Field index 0 is out of bounds for length 0 at com.comphenix.protocol.reflect.FieldAccessException.fromFormat(FieldAccessException.java:49) ~[ProtocolLib.jar:?] at com.comphenix.protocol.reflect.StructureModifier.write(StructureModifier.java:315) ~[ProtocolLib.jar:?]
I print the packet.getStrings().size(), and its result is 0.I don't know why.And I want to know how to write a correctly code.

What Minecraft version are you running? This error could be caused by an outdated version of ProtocolLib.
Try downloading the latest build: here