Macro define_plugin 

macro_rules! define_plugin {
    (
        init: $init_fn:path,
        shutdown: $shutdown_fn:path,
        entries: {
            $($entry_name:literal => $handler_fn:path),* $(,)?
        }
        $(, stream_handlers: {
            data: $stream_data_fn:path,
            close: $stream_close_fn:path $(,)?
        })?
    ) => { ... };
}