Add rosidl_runtime_rs::ActionImpl::create_feedback_message()

Adds a trait method to create a feedback message given the goal ID and
the user-facing feedback message type. Depending on how many times we do
this, it may end up valuable to define a GoalUuid type in
rosidl_runtime_rs itself. We wouldn't be able to utilize the
`RCL_ACTION_UUID_SIZE` constant imported from `rcl_action`, but this is
pretty much guaranteed to be 16 forever.

Defining this method signature also required inverting the super-trait
relationship between Action and ActionImpl. Now ActionImpl is the
sub-trait as this gives it access to all of Action's associated types.
Action doesn't need to care about anything from ActionImpl (hopefully).

Author: nwn

rclrs/src/action/server.rs

@@ -83,7 +83,7 @@ where
 
 impl<T> ActionServer<T>
 where
-    T: rosidl_runtime_rs::Action,
+    T: rosidl_runtime_rs::Action + rosidl_runtime_rs::ActionImpl,
 {
     /// Creates a new action server.
     pub(crate) fn new(
@@ -95,7 +95,7 @@ where
         accepted_callback: impl Fn(ServerGoalHandle<T>) + 'static + Send + Sync,
     ) -> Result<Self, RclrsError>
     where
-        T: rosidl_runtime_rs::Action,
+        T: rosidl_runtime_rs::Action + rosidl_runtime_rs::ActionImpl,
     {
         // SAFETY: Getting a zero-initialized value is always safe.
         let mut rcl_action_server = unsafe { rcl_action_get_zero_initialized_server() };
@@ -335,7 +335,7 @@ where
 
 impl<T> ActionServerBase for ActionServer<T>
 where
-    T: rosidl_runtime_rs::Action,
+    T: rosidl_runtime_rs::Action + rosidl_runtime_rs::ActionImpl,
 {
     fn handle(&self) -> &ActionServerHandle {
         &self.handle

rclrs/src/node.rs

@@ -323,7 +323,7 @@ impl NodeState {
         handle_accepted: AcceptedCallback,
     ) -> Result<Arc<ActionServer<ActionT>>, RclrsError>
     where
-        ActionT: rosidl_runtime_rs::Action,
+        ActionT: rosidl_runtime_rs::Action + rosidl_runtime_rs::ActionImpl,
         GoalCallback: Fn(GoalUuid, <ActionT as rosidl_runtime_rs::Action>::Goal) -> GoalResponse + 'static + Send + Sync,
         CancelCallback: Fn(ServerGoalHandle<ActionT>) -> CancelResponse + 'static + Send + Sync,
         AcceptedCallback: Fn(ServerGoalHandle<ActionT>) + 'static + Send + Sync,