Shortcut pending hook activation on first data

src/protocol/tree/endpoint/hooks.rs

@@ -60,8 +60,18 @@ impl ProtocolEndpoint {
             pending.caller_src_path == header.src_path
                 && pending.procedure_id == message.procedure_id
         }) {
-            self.hooks.activate_pending(&host_key);
-            host_key
+            let local_ended = self
+                .hooks
+                .activate_pending_with_peer_end(&host_key, message.end_hook)
+                .expect("pending hook was checked above");
+            if message.end_hook && local_ended {
+                self.hooks.remove_active(&host_key);
+            }
+            return Ok(EndpointOutcome::Local(LocalEvent::Data {
+                header,
+                message,
+                hook_key: host_key,
+            }));
         } else {
             return Ok(EndpointOutcome::Dropped);
         };

src/protocol/tree/hook.rs

@@ -98,18 +98,29 @@ impl HookTable {
     /// Activation intentionally reuses the original hook id and host path, but swaps the
     /// pending caller attribution into the active peer path used for data routing.
     pub fn activate_pending(&mut self, key: &HookKey) -> Option<()> {
+        self.activate_pending_with_peer_end(key, false).map(|_| ())
+    }
+
+    /// Promotes a pending hook into the active table and returns whether the local side had
+    /// already ended before the peer accepted the hook.
+    pub fn activate_pending_with_peer_end(
+        &mut self,
+        key: &HookKey,
+        peer_ended: bool,
+    ) -> Option<bool> {
         let pending = self.pending.remove(key)?;
+        let local_ended = pending.local_ended;
         self.insert_active(
             key.clone(),
             ActiveHook {
                 peer_path: pending.caller_src_path,
                 procedure_id: pending.procedure_id,
-                local_ended: pending.local_ended,
-                peer_ended: false,
+                local_ended,
+                peer_ended,
             },
         )
         .ok()?;
-        Some(())
+        Some(local_ended)
     }
 
     /// Inserts a live hook and its peer-path lookup entry.