* Foo& foo = myFoo.getOrCreateFn(evb, [] () { return new Foo(3, 4); })
*
* The objects will be deleted when the EventBaseLocal or the EventBase is
- * destructed (whichever comes first). All methods are thread-safe.
+ * destructed (whichever comes first). All methods must be called from the
+ * EventBase thread.
*
* The user is responsible for throwing away invalid references/ptrs returned
* by the get() method after set/erase is called. If shared ownership is