ProtocolLib

public class ExampleMod extends JavaPlugin {
    private final UUID SPRITING_SPEED = UUID.fromString(
        "662a6b8d-da3e-4c1c-8813-96ea6097278d");
    private final UUID SUPER_SPRINTING = UUID.fromString(
        "d64c79c2-a459-446c-9308-409e1b6b3340");
    
    public void onEnable() {
        ProtocolLibrary.getProtocolManager().addPacketListener(
          new PacketAdapter(PacketAdapter.params(this, 
            Packets.Server.UPDATE_ATTRIBUTES).serverSide()) {
            public void onPacketSending(PacketEvent event) {
                List<WrappedAttribute> list = event.getPacket()
                        .getAttributeCollectionModifier().read(0);

                for (int i = 0; i < list.size(); i++) {
                    WrappedAttribute attribute = list.get(i);

                    // See if we should add the super sprinting
                    // attribute
                    if (attribute.hasModifier(SPRITING_SPEED) && 
                       !attribute.hasModifier(SUPER_SPRINTING)) {
                        Set<WrappedAttributeModifier> modifiers = 
                            Sets.newHashSet(attribute.getModifiers());

                        // Add the new super sprinting too
                        modifiers.add(WrappedAttributeModifier.newBuilder().
                            name("Super Sprinting").uuid(SUPER_SPRINTING).
                            amount(2).
                            operation(Operation.ADD_PERCENTAGE).
                            build());

                        list.set(i, attribute.withModifiers(modifiers));
                    }
                }

                event.getPacket().
                    getAttributeCollectionModifier().write(0, list);
            }
        });
    }
}