refactor: rcmd hot

lib/http/loading_state.dart

@@ -0,0 +1,26 @@
+abstract class LoadingState<T> {
+  const LoadingState();
+
+  factory LoadingState.loading() = Loading;
+  factory LoadingState.empty() = Empty;
+  factory LoadingState.success(T response) = Success<T>;
+  factory LoadingState.error(String errMsg) = Error;
+}
+
+class Loading extends LoadingState<Never> {
+  const Loading();
+}
+
+class Empty extends LoadingState<Never> {
+  const Empty();
+}
+
+class Success<T> extends LoadingState<T> {
+  final T response;
+  const Success(this.response);
+}
+
+class Error extends LoadingState<Never> {
+  final String errMsg;
+  const Error(this.errMsg);
+}