An example of creating a channel for sending commands to self.

sample_send_self.rs

    let (self_commands, mut self_commands_receiver) = mpsc::unbounded_channel();
    let (entity_manager_task, commands) = entity_manager::task(
        Behavior {
            self_commands,
        },
        file_log_topic_adapter,
        MAX_COMMANDS,
        MAX_ENTITIES,
    );
    let task_commands = commands.clone().downgrade();
    let self_commands_forwarder_task = async move {
        while let Some(message) = self_commands_receiver.recv().await {
            if let Some(task_commands) = task_commands.upgrade() {
                let _ = task_commands.send(message).await;
            }
        }
    };
    let handle =
        tokio::spawn(async { tokio::join!(entity_manager_task, self_commands_forwarder_task).0 });