Macro export 

macro_rules! export {
    ($plugin:ty) => { ... };
    ($plugin:ty, chat) => { ... };
}

Exports a Plugin implementation as the component’s rift:plugin/handler interface. Use it exactly once per plugin crate.

rift_plugin::export!(MyPlugin);

export!(MyPlugin, chat) also exports Plugin::chat as the optional rift:plugin/chat interface. Rift asks a component with that export about every chat message and starts it only with authentication.signed_chat = false, so add it only to a plugin that moderates chat.