embedded-service/event: Break up existing Sender trait

[RobertZ2011]

Break-out non-blocking send function into NonBlockingSender trait. Introduce Immediate wrapper to distinguish receivers that can implement some sort of recovery flow if events are dropped.

[Copilot]

Pull request overview

This PR refactors the workspace’s event API by separating non-blocking sends from blocking sends, and updates multiple services/controllers to use the new non-blocking try_send style. It also introduces an “immediate event” wrapper type to allow receivers to detect lag for immediate pubsub subscribers.

Changes:

• Split embedded_services::event::Sender into non-blocking Sender::try_send and new BlockingSender::send.
• Introduce ImmediateEvent<E> and implement Receiver<ImmediateEvent<E>> for DynSubscriber to surface lagged-message counts.
• Update Type-C, power-policy, and thermal services/controllers to replace .send(...).await with try_send(...) and log on failure.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
type-c-service/src/service/ucsi.rs	Adjust UCSI codepaths to call the now-sync broadcast without awaiting.
type-c-service/src/service/mod.rs	Make service broadcast non-blocking via try_send and log on failure.
type-c-service/src/controller/power.rs	Convert power-policy event emission to try_send and log on failure.
type-c-service/src/controller/pd.rs	Convert Type-C event emission for VDM/DP/Alert to try_send and log on failure.
type-c-service/src/controller/mod.rs	Convert port status/power-policy/loopback notifications to try_send.
type-c-service/src/controller/event_receiver.rs	Convert interrupt splitting forwarding to try_send and log on failure.
thermal-service/src/sensor.rs	Convert sensor event broadcast to non-blocking try_send.
thermal-service/src/fan.rs	Convert fan event broadcast to non-blocking try_send.
power-policy-service/src/service/provider.rs	Make post-connect/disconnect broadcast path sync/non-blocking.
power-policy-service/src/service/mod.rs	Make service broadcast non-blocking via try_send and log on failure.
power-policy-service/src/service/consumer.rs	Update consumer flows to call sync/non-blocking broadcast.
embedded-service/src/event.rs	Add BlockingSender, add ImmediateEvent, and adjust sender/receiver impls accordingly.

[RobertZ2011]

@kurtjd Let me know if this change should apply to the thermal service or if that should use the BlockingSender trait.

[tullom]

Code changes look good, Kurtis should sign off on this for the thermal service changes

[kurtjd]

Was part of the motivation for this to make the NonBlockingSender dyn compatible? At least, this does have the nice side effect now of making it easier to pass a heterogeneous sender list to a service without needing enum dispatch.

[RobertZ2011]

Fixed minor merge conflicts from rebasing.

[RobertZ2011]

Was part of the motivation for this to make the NonBlockingSender dyn compatible?

Not really, the primary goal was to encode more information into the traits, particularly around behavior when a channel fills up.