MessageBroker: refactor to an immediate mode API

Cargo.lock

Cargo.toml

src/main.rs

src/mavlink.rs

src/message_broker.rs

src/message_broker/message_bundle.rs

src/message_broker/reception_queue.rs

src/ui/composable_view.rs

src/ui/panes.rs

src/ui/panes/default.rs

src/ui/panes/messages_viewer.rs

src/ui/panes/plot.rs

src/ui/persistency/layout_manager.rs

src/ui/widgets/reception_led.rs