Simplify interface event recording.

src/interface/mod.rs

@@ -6,7 +6,6 @@
 mod event;
 mod key;
 mod store;
-mod target;
 mod view;
 
 pub use event::{InterfaceEvent, InterfaceEventKind};
@@ -14,4 +13,4 @@ pub use key::{ProcedureKey, SessionKey};
 pub use store::InterfaceStore;
 pub use view::{ProcedureView, SessionView, SessionViewStatus};
 
-pub(crate) use target::InterfaceTarget;
+pub(crate) use store::InterfaceTarget;

src/interface/store.rs

@@ -2,12 +2,54 @@ use alloc::{collections::BTreeMap, vec::Vec};
 
 use crate::{
     interface::{
-        InterfaceEvent, InterfaceEventKind, InterfaceTarget, ProcedureKey, ProcedureView,
-        SessionKey, SessionView, SessionViewStatus,
+        InterfaceEvent, InterfaceEventKind, ProcedureKey, ProcedureView, SessionKey, SessionView,
+        SessionViewStatus,
     },
     protocol::{EndpointError, HookID, Packet, SessionStatus},
 };
 
+/// Internal owner for one interface event.
+///
+/// The runtime already knows whether a packet belongs to a hook-backed session or a
+/// one-shot procedure. Keeping that answer explicit avoids reconstructing ownership
+/// from packet fields later, which is what made procedure packet flow look like fake
+/// session activity in the previous store implementation.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub(crate) enum InterfaceTarget {
+    /// Event belongs to one hook-backed session instance.
+    Session(SessionKey),
+
+    /// Event belongs to one one-shot procedure family.
+    Procedure(ProcedureKey),
+}
+
+impl InterfaceTarget {
+    /// Builds a session target from the same pieces exposed by [`SessionKey`].
+    pub(crate) fn session(leaf_id: u32, procedure_id: u32, hook_id: HookID) -> Self {
+        Self::Session(SessionKey {
+            leaf_id,
+            procedure_id,
+            hook_id,
+        })
+    }
+
+    /// Builds a procedure target from the same pieces exposed by [`ProcedureKey`].
+    pub(crate) fn procedure(leaf_id: u32, procedure_id: u32) -> Self {
+        Self::Procedure(ProcedureKey {
+            leaf_id,
+            procedure_id,
+        })
+    }
+
+    /// Returns the leaf id used on the append-only event record.
+    pub(crate) fn leaf_id(self) -> u32 {
+        match self {
+            Self::Session(key) => key.leaf_id,
+            Self::Procedure(key) => key.leaf_id,
+        }
+    }
+}
+
 /// Caller-owned view and packet-flow store for interface frontends.
 ///
 /// Generated leaves receive a mutable reference to this store during interface-aware
@@ -86,14 +128,8 @@ impl InterfaceStore {
     /// Records a packet delivered to a generated leaf.
     pub fn record_inbound(&mut self, leaf_id: u32, packet: &Packet) {
         let target = InterfaceTarget::session(leaf_id, packet.procedure_id, packet.hook_id);
-        self.record_inbound_for(target, packet);
-    }
-
-    /// Records a packet delivered to a target already known by generated runtime code.
-    pub(crate) fn record_inbound_for(&mut self, target: InterfaceTarget, packet: &Packet) {
-        self.record(
+        self.record_for(
             target,
-            None,
             InterfaceEventKind::Inbound {
                 packet: packet.clone(),
             },
@@ -107,25 +143,11 @@ impl InterfaceStore {
         procedure_id: u32,
         hook_id: HookID,
     ) {
-        self.record_session_packet_queued_for(InterfaceTarget::session(
-            leaf_id,
+        self.record_for(
+            InterfaceTarget::session(leaf_id, procedure_id, hook_id),
+            InterfaceEventKind::SessionPacketQueued {
                 procedure_id,
                 hook_id,
-        ));
-    }
-
-    /// Records that a packet was queued for an existing session inbox.
-    pub(crate) fn record_session_packet_queued_for(&mut self, target: InterfaceTarget) {
-        let InterfaceTarget::Session(key) = target else {
-            return;
-        };
-
-        self.record(
-            target,
-            None,
-            InterfaceEventKind::SessionPacketQueued {
-                procedure_id: key.procedure_id,
-                hook_id: key.hook_id,
             },
         );
     }
@@ -138,26 +160,11 @@ impl InterfaceStore {
         hook_id: HookID,
         started_ns: Option<u64>,
     ) {
-        let target = InterfaceTarget::session(leaf_id, procedure_id, hook_id);
-        self.record_session_created_for(target, started_ns);
-    }
-
-    /// Records successful creation of a new session state for an explicit target.
-    pub(crate) fn record_session_created_for(
-        &mut self,
-        target: InterfaceTarget,
-        started_ns: Option<u64>,
-    ) {
-        let InterfaceTarget::Session(key) = target else {
-            return;
-        };
-
-        self.record(
-            target,
-            Some(SessionViewStatus::Running),
+        self.record_for(
+            InterfaceTarget::session(leaf_id, procedure_id, hook_id),
             InterfaceEventKind::SessionCreated {
-                procedure_id: key.procedure_id,
-                hook_id: key.hook_id,
+                procedure_id,
+                hook_id,
                 started_ns,
                 finished_ns: self.now_ns,
             },
@@ -172,26 +179,11 @@ impl InterfaceStore {
         hook_id: HookID,
         started_ns: Option<u64>,
     ) {
-        let target = InterfaceTarget::session(leaf_id, procedure_id, hook_id);
-        self.record_session_rejected_for(target, started_ns);
-    }
-
-    /// Records rejection of a packet that could not create a session.
-    pub(crate) fn record_session_rejected_for(
-        &mut self,
-        target: InterfaceTarget,
-        started_ns: Option<u64>,
-    ) {
-        let InterfaceTarget::Session(key) = target else {
-            return;
-        };
-
-        self.record(
-            target,
-            Some(SessionViewStatus::Rejected),
+        self.record_for(
+            InterfaceTarget::session(leaf_id, procedure_id, hook_id),
             InterfaceEventKind::SessionRejected {
-                procedure_id: key.procedure_id,
-                hook_id: key.hook_id,
+                procedure_id,
+                hook_id,
                 started_ns,
                 finished_ns: self.now_ns,
             },
@@ -207,27 +199,11 @@ impl InterfaceStore {
         status: SessionStatus,
         started_ns: Option<u64>,
     ) {
-        let target = InterfaceTarget::session(leaf_id, procedure_id, hook_id);
-        self.record_session_update_for(target, status, started_ns);
-    }
-
-    /// Records one session update tick for an explicit session target.
-    pub(crate) fn record_session_update_for(
-        &mut self,
-        target: InterfaceTarget,
-        status: SessionStatus,
-        started_ns: Option<u64>,
-    ) {
-        let InterfaceTarget::Session(key) = target else {
-            return;
-        };
-
-        self.record(
-            target,
-            Some(SessionViewStatus::from_session_status(status)),
+        self.record_for(
+            InterfaceTarget::session(leaf_id, procedure_id, hook_id),
             InterfaceEventKind::SessionUpdated {
-                procedure_id: key.procedure_id,
-                hook_id: key.hook_id,
+                procedure_id,
+                hook_id,
                 status,
                 started_ns,
                 finished_ns: self.now_ns,
@@ -243,29 +219,10 @@ impl InterfaceStore {
         hook_id: HookID,
         started_ns: Option<u64>,
     ) {
-        self.record_procedure_call_for(
+        self.record_for(
             InterfaceTarget::procedure(leaf_id, procedure_id),
-            hook_id,
-            started_ns,
-        );
-    }
-
-    /// Records one procedure call for an explicit procedure target.
-    pub(crate) fn record_procedure_call_for(
-        &mut self,
-        target: InterfaceTarget,
-        hook_id: HookID,
-        started_ns: Option<u64>,
-    ) {
-        let InterfaceTarget::Procedure(key) = target else {
-            return;
-        };
-
-        self.record(
-            target,
-            None,
             InterfaceEventKind::ProcedureCalled {
-                procedure_id: key.procedure_id,
+                procedure_id,
                 hook_id,
                 started_ns,
                 finished_ns: self.now_ns,
@@ -276,14 +233,8 @@ impl InterfaceStore {
     /// Records a packet emitted by leaf logic before route retry handling.
     pub fn record_outbound_queued(&mut self, leaf_id: u32, packet: &Packet) {
         let target = InterfaceTarget::session(leaf_id, packet.procedure_id, packet.hook_id);
-        self.record_outbound_queued_for(target, packet);
-    }
-
-    /// Records a packet emitted by leaf logic before route retry handling.
-    pub(crate) fn record_outbound_queued_for(&mut self, target: InterfaceTarget, packet: &Packet) {
-        self.record(
+        self.record_for(
             target,
-            None,
             InterfaceEventKind::OutboundQueued {
                 packet: packet.clone(),
             },
@@ -293,14 +244,8 @@ impl InterfaceStore {
     /// Records a route attempt for a queued outbound packet.
     pub fn record_route_attempt(&mut self, leaf_id: u32, packet: &Packet) {
         let target = InterfaceTarget::session(leaf_id, packet.procedure_id, packet.hook_id);
-        self.record_route_attempt_for(target, packet);
-    }
-
-    /// Records a route attempt for a queued outbound packet.
-    pub(crate) fn record_route_attempt_for(&mut self, target: InterfaceTarget, packet: &Packet) {
-        self.record(
+        self.record_for(
             target,
-            None,
             InterfaceEventKind::RouteAttempt {
                 packet: packet.clone(),
             },
@@ -310,14 +255,8 @@ impl InterfaceStore {
     /// Records a successful route attempt.
     pub fn record_route_success(&mut self, leaf_id: u32, packet: &Packet) {
         let target = InterfaceTarget::session(leaf_id, packet.procedure_id, packet.hook_id);
-        self.record_route_success_for(target, packet);
-    }
-
-    /// Records a successful route attempt.
-    pub(crate) fn record_route_success_for(&mut self, target: InterfaceTarget, packet: &Packet) {
-        self.record(
+        self.record_for(
             target,
-            None,
             InterfaceEventKind::RouteSuccess {
                 packet: packet.clone(),
             },
@@ -327,19 +266,8 @@ impl InterfaceStore {
     /// Records a failed route attempt without removing the packet from retry state.
     pub fn record_route_failure(&mut self, leaf_id: u32, packet: &Packet, error: EndpointError) {
         let target = InterfaceTarget::session(leaf_id, packet.procedure_id, packet.hook_id);
-        self.record_route_failure_for(target, packet, error);
-    }
-
-    /// Records a failed route attempt without removing the packet from retry state.
-    pub(crate) fn record_route_failure_for(
-        &mut self,
-        target: InterfaceTarget,
-        packet: &Packet,
-        error: EndpointError,
-    ) {
-        self.record(
+        self.record_for(
             target,
-            None,
             InterfaceEventKind::RouteFailure {
                 packet: packet.clone(),
                 error,
@@ -347,22 +275,14 @@ impl InterfaceStore {
         );
     }
 
-    fn record(
-        &mut self,
-        target: InterfaceTarget,
-        status: Option<SessionViewStatus>,
-        kind: InterfaceEventKind,
-    ) {
+    pub(crate) fn record_for(&mut self, target: InterfaceTarget, kind: InterfaceEventKind) {
         let index = self.push_event(target.leaf_id(), kind);
-        self.link_event(target, status, index);
+        self.link_event(target, index);
     }
 
-    fn link_event(
-        &mut self,
-        target: InterfaceTarget,
-        status: Option<SessionViewStatus>,
-        index: usize,
-    ) {
+    fn link_event(&mut self, target: InterfaceTarget, index: usize) {
+        let status = Self::status_for_event(&self.events[index].kind);
+
         match target {
             InterfaceTarget::Session(key) => {
                 let view = self.session_view_for_key_mut(key);
@@ -379,6 +299,17 @@ impl InterfaceStore {
         }
     }
 
+    fn status_for_event(kind: &InterfaceEventKind) -> Option<SessionViewStatus> {
+        match kind {
+            InterfaceEventKind::SessionCreated { .. } => Some(SessionViewStatus::Running),
+            InterfaceEventKind::SessionRejected { .. } => Some(SessionViewStatus::Rejected),
+            InterfaceEventKind::SessionUpdated { status, .. } => {
+                Some(SessionViewStatus::from_session_status(*status))
+            }
+            _ => None,
+        }
+    }
+
     fn push_event(&mut self, leaf_id: u32, kind: InterfaceEventKind) -> usize {
         let index = self.events.len();
 

src/interface/target.rs

@@ -1,46 +0,0 @@
-use crate::{
-    interface::{ProcedureKey, SessionKey},
-    protocol::HookID,
-};
-
-/// Internal owner for one interface event.
-///
-/// The runtime already knows whether a packet belongs to a hook-backed session or a
-/// one-shot procedure. Keeping that answer explicit avoids reconstructing ownership
-/// from packet fields later, which is what made procedure packet flow look like fake
-/// session activity in the previous store implementation.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub(crate) enum InterfaceTarget {
-    /// Event belongs to one hook-backed session instance.
-    Session(SessionKey),
-
-    /// Event belongs to one one-shot procedure family.
-    Procedure(ProcedureKey),
-}
-
-impl InterfaceTarget {
-    /// Builds a session target from the same pieces exposed by [`SessionKey`].
-    pub(crate) fn session(leaf_id: u32, procedure_id: u32, hook_id: HookID) -> Self {
-        Self::Session(SessionKey {
-            leaf_id,
-            procedure_id,
-            hook_id,
-        })
-    }
-
-    /// Builds a procedure target from the same pieces exposed by [`ProcedureKey`].
-    pub(crate) fn procedure(leaf_id: u32, procedure_id: u32) -> Self {
-        Self::Procedure(ProcedureKey {
-            leaf_id,
-            procedure_id,
-        })
-    }
-
-    /// Returns the leaf id used on the append-only event record.
-    pub(crate) fn leaf_id(self) -> u32 {
-        match self {
-            Self::Session(key) => key.leaf_id,
-            Self::Procedure(key) => key.leaf_id,
-        }
-    }
-}

src/protocol/runtime.rs

@@ -1,7 +1,7 @@
 use alloc::collections::VecDeque;
 
 use crate::{
-    interface::{InterfaceStore, InterfaceTarget},
+    interface::{InterfaceEventKind, InterfaceStore, InterfaceTarget},
     protocol::{
         Endpoint, Packet, PacketQueue, Procedure, ProcedureOut, Session, SessionCtx, SessionEntry,
         SessionFamily, SessionInit, SessionInitResult, SessionStatus,
@@ -26,17 +26,7 @@ pub struct LeafOutbox {
 #[derive(Clone)]
 struct LeafOutboxEntry {
     packet: Packet,
-    target: LeafOutboxTarget,
-}
-
-/// Interface owner attached to a leaf-level outbox entry.
-#[derive(Clone, Copy)]
-enum LeafOutboxTarget {
-    /// Compatibility path for packets queued through the public `push`/`extend` API.
-    InferFromPacket,
-
-    /// Runtime-known session or procedure target.
-    Explicit(InterfaceTarget),
+    target: Option<InterfaceTarget>,
 }
 
 impl LeafOutbox {
@@ -49,7 +39,7 @@ impl LeafOutbox {
 
     /// Adds one packet to the retry queue.
     pub fn push(&mut self, packet: Packet) {
-        self.push_with_target(packet, LeafOutboxTarget::InferFromPacket);
+        self.push_with_target(packet, None);
     }
 
     /// Adds all packets from `packets` in FIFO order.
@@ -71,7 +61,11 @@ impl LeafOutbox {
 
     /// Adds one packet with a runtime-known interface target.
     pub(crate) fn push_for_target(&mut self, packet: Packet, target: InterfaceTarget) {
-        self.push_with_target(packet, LeafOutboxTarget::Explicit(target));
+        self.push_with_target(packet, Some(target));
+    }
+
+    fn push_with_target(&mut self, packet: Packet, target: Option<InterfaceTarget>) {
+        self.packets.push_back(LeafOutboxEntry { packet, target });
     }
 
     /// Adds all packets with the same runtime-known interface target.
@@ -80,10 +74,6 @@ impl LeafOutbox {
             self.push_for_target(packet, target);
         }
     }
-
-    fn push_with_target(&mut self, packet: Packet, target: LeafOutboxTarget) {
-        self.packets.push_back(LeafOutboxEntry { packet, target });
-    }
 }
 
 impl Default for LeafOutbox {
@@ -112,7 +102,12 @@ pub fn dispatch_session<L, S>(
     let target = InterfaceTarget::session(leaf_id, procedure_id, hook_id);
 
     if let Some(store) = interface.as_mut() {
-        store.record_inbound_for(target, &packet);
+        store.record_for(
+            target,
+            InterfaceEventKind::Inbound {
+                packet: packet.clone(),
+            },
+        );
     }
 
     if let Some(entry) = family
@@ -123,7 +118,13 @@ pub fn dispatch_session<L, S>(
         entry.inbox.push_back(packet);
 
         if let Some(store) = interface.as_mut() {
-            store.record_session_packet_queued_for(target);
+            store.record_for(
+                target,
+                InterfaceEventKind::SessionPacketQueued {
+                    procedure_id,
+                    hook_id,
+                },
+            );
         }
 
         return;
@@ -138,18 +139,47 @@ pub fn dispatch_session<L, S>(
             family.entries.push(SessionEntry::new(hook_id, state));
 
             if let Some(store) = interface.as_mut() {
-                store.record_session_created_for(target, started_ns);
+                store.record_for(
+                    target,
+                    InterfaceEventKind::SessionCreated {
+                        procedure_id,
+                        hook_id,
+                        started_ns,
+                        finished_ns: store.now_ns(),
+                    },
+                );
             }
         }
         SessionInitResult::Rejected => {
             if let Some(store) = interface.as_mut() {
-                store.record_session_rejected_for(target, started_ns);
+                store.record_for(
+                    target,
+                    InterfaceEventKind::SessionRejected {
+                        procedure_id,
+                        hook_id,
+                        started_ns,
+                        finished_ns: store.now_ns(),
+                    },
+                );
             }
         }
         SessionInitResult::RejectedWith(packet) => {
             if let Some(store) = interface.as_mut() {
-                store.record_session_rejected_for(target, started_ns);
-                store.record_outbound_queued_for(target, &packet);
+                store.record_for(
+                    target,
+                    InterfaceEventKind::SessionRejected {
+                        procedure_id,
+                        hook_id,
+                        started_ns,
+                        finished_ns: store.now_ns(),
+                    },
+                );
+                store.record_for(
+                    target,
+                    InterfaceEventKind::OutboundQueued {
+                        packet: packet.clone(),
+                    },
+                );
             }
 
             outbox.push_for_target(packet, target);
@@ -187,10 +217,24 @@ pub fn update_session_family<L, S>(
         let target = InterfaceTarget::session(leaf_id, S::PROCEDURE_ID, entry.hook_id);
 
         if let Some(store) = interface.as_mut() {
-            store.record_session_update_for(target, status, started_ns);
+            store.record_for(
+                target,
+                InterfaceEventKind::SessionUpdated {
+                    procedure_id: S::PROCEDURE_ID,
+                    hook_id: entry.hook_id,
+                    status,
+                    started_ns,
+                    finished_ns: store.now_ns(),
+                },
+            );
 
             for packet in entry.outbox.iter().skip(outbox_start) {
-                store.record_outbound_queued_for(target, packet);
+                store.record_for(
+                    target,
+                    InterfaceEventKind::OutboundQueued {
+                        packet: packet.clone(),
+                    },
+                );
             }
         }
 
@@ -215,7 +259,12 @@ pub fn dispatch_procedure<L, P>(
     let target = InterfaceTarget::procedure(leaf_id, P::PROCEDURE_ID);
 
     if let Some(store) = interface.as_mut() {
-        store.record_inbound_for(target, &packet);
+        store.record_for(
+            target,
+            InterfaceEventKind::Inbound {
+                packet: packet.clone(),
+            },
+        );
     }
 
     let hook_id = packet.hook_id;
@@ -227,10 +276,23 @@ pub fn dispatch_procedure<L, P>(
     let packets = procedure_out.into_packets();
 
     if let Some(store) = interface.as_mut() {
-        store.record_procedure_call_for(target, hook_id, started_ns);
+        store.record_for(
+            target,
+            InterfaceEventKind::ProcedureCalled {
+                procedure_id: P::PROCEDURE_ID,
+                hook_id,
+                started_ns,
+                finished_ns: store.now_ns(),
+            },
+        );
 
         for packet in &packets {
-            store.record_outbound_queued_for(target, packet);
+            store.record_for(
+                target,
+                InterfaceEventKind::OutboundQueued {
+                    packet: packet.clone(),
+                },
+            );
         }
     }
 
@@ -244,17 +306,13 @@ pub fn flush_leaf_outbox(
     outbox: &mut LeafOutbox,
     interface: &mut Option<&mut InterfaceStore>,
 ) -> bool {
-    while let Some(entry) = outbox.packets.front().cloned() {
-        let target = resolve_leaf_outbox_target(leaf_id, &entry);
+    flush_outbox(endpoint, &mut outbox.packets, interface, |entry| {
+        let target = entry.target.unwrap_or_else(|| {
+            InterfaceTarget::session(leaf_id, entry.packet.procedure_id, entry.packet.hook_id)
+        });
 
-        if !flush_packet_with_target(endpoint, target, &entry.packet, interface) {
-            return false;
-        }
-
-        outbox.packets.pop_front();
-    }
-
-    true
+        (target, entry.packet.clone())
+    })
 }
 
 /// Flushes and retains one generated session family.
@@ -287,17 +345,12 @@ pub fn flush_packet_queue_with_interface(
     outbox: &mut PacketQueue,
     interface: &mut Option<&mut InterfaceStore>,
 ) -> bool {
-    while let Some(packet) = outbox.front().cloned() {
-        let target = InterfaceTarget::session(leaf_id, packet.procedure_id, packet.hook_id);
-
-        if !flush_packet_with_target(endpoint, target, &packet, interface) {
-            return false;
-        }
-
-        outbox.pop_front();
-    }
-
-    true
+    flush_outbox(endpoint, outbox, interface, |packet| {
+        (
+            InterfaceTarget::session(leaf_id, packet.procedure_id, packet.hook_id),
+            packet.clone(),
+        )
+    })
 }
 
 /// Flushes a packet queue whose owner is already known by the generated runtime.
@@ -307,7 +360,20 @@ fn flush_packet_queue_with_target(
     outbox: &mut PacketQueue,
     interface: &mut Option<&mut InterfaceStore>,
 ) -> bool {
-    while let Some(packet) = outbox.front().cloned() {
+    flush_outbox(endpoint, outbox, interface, |packet| {
+        (target, packet.clone())
+    })
+}
+
+fn flush_outbox<T>(
+    endpoint: &mut Endpoint,
+    outbox: &mut VecDeque<T>,
+    interface: &mut Option<&mut InterfaceStore>,
+    mut packet_for: impl FnMut(&T) -> (InterfaceTarget, Packet),
+) -> bool {
+    while let Some(item) = outbox.front() {
+        let (target, packet) = packet_for(item);
+
         if !flush_packet_with_target(endpoint, target, &packet, interface) {
             return false;
         }
@@ -325,20 +391,36 @@ fn flush_packet_with_target(
     interface: &mut Option<&mut InterfaceStore>,
 ) -> bool {
     if let Some(store) = interface.as_mut() {
-        store.record_route_attempt_for(target, packet);
+        store.record_for(
+            target,
+            InterfaceEventKind::RouteAttempt {
+                packet: packet.clone(),
+            },
+        );
     }
 
     match endpoint.add_outbound(packet.clone()) {
         Ok(()) => {
             if let Some(store) = interface.as_mut() {
-                store.record_route_success_for(target, packet);
+                store.record_for(
+                    target,
+                    InterfaceEventKind::RouteSuccess {
+                        packet: packet.clone(),
+                    },
+                );
             }
 
             true
         }
         Err(error) => {
             if let Some(store) = interface.as_mut() {
-                store.record_route_failure_for(target, packet, error);
+                store.record_for(
+                    target,
+                    InterfaceEventKind::RouteFailure {
+                        packet: packet.clone(),
+                        error,
+                    },
+                );
             }
 
             false
@@ -346,15 +428,6 @@ fn flush_packet_with_target(
     }
 }
 
-fn resolve_leaf_outbox_target(leaf_id: u32, entry: &LeafOutboxEntry) -> InterfaceTarget {
-    match entry.target {
-        LeafOutboxTarget::InferFromPacket => {
-            InterfaceTarget::session(leaf_id, entry.packet.procedure_id, entry.packet.hook_id)
-        }
-        LeafOutboxTarget::Explicit(target) => target,
-    }
-}
-
 /// Returns the path used by generated procedure responses.
 fn parent_reply_path(endpoint: &Endpoint) -> alloc::vec::Vec<u32> {
     if endpoint.path.len() > 1 {