add constructor for lazy-loading service

src/service.rs

@@ -1,5 +1,5 @@
 use std::{
-    collections::{BTreeMap, HashMap},
+    collections::BTreeMap,
     sync::{Arc, Mutex as StdMutex, OnceLock},
 };
 
@@ -88,10 +88,7 @@ impl Services {
                     typing: rooms::edus::typing::Service::new(),
                 },
                 event_handler: rooms::event_handler::Service,
-                lazy_loading: rooms::lazy_loading::Service {
-                    db,
-                    lazy_load_waiting: Mutex::new(HashMap::new()),
-                },
+                lazy_loading: rooms::lazy_loading::Service::new(db),
                 metadata: db,
                 outlier: db,
                 pdu_metadata: rooms::pdu_metadata::Service {