improve log

LeStorage/Store.swift

@@ -271,6 +271,14 @@ final public class Store {
         }
     }
     
+    func isRegistered() -> Bool {
+        if let identifier {
+            return self.storeCenter.isStoreRegistered(id: identifier)
+        } else {
+            return true
+        }
+    }
+    
     // MARK: - Synchronization
     
     fileprivate func _requestWrite<T: SyncedStorable>(type: T.Type) {

LeStorage/StoreCenter.swift

@@ -224,6 +224,10 @@ public class StoreCenter {
     public func destroyStore(identifier: String) {
         self._storeLibrary.destroyStore(identifier: identifier)
     }
+    
+    func isStoreRegistered(id: String) -> Bool {
+        return self._storeLibrary[id] != nil
+    }
 
     // MARK: - Settings
 

LeStorage/StoredCollection.swift

@@ -529,7 +529,7 @@ public class StoredCollection<T: Storable>: SomeCollection {
             } catch {
                 Logger.error(error)
                 self.storeCenter.log(
-                    message: "write failed for \(T.resourceName()): \(error.localizedDescription)")
+                    message: "write failed for \(T.resourceName()): \(error.localizedDescription) / store registered \(self.store.isRegistered()), id = \(String(describing: self.store.identifier))")
             }
         }
         self._cleanTimer()