// 等效于用addCase手动写多个：
builder
.addCase('user/fetch/pending', (state) => { ... })
.addCase('posts/load/pending', (state) => { ... })
.addCase('comments/update/pending', (state) => { ... });
// 但用addMatcher只需要：
builder.addMatcher(
(action) => action.type.endsWith('/pending'),
(state) => { ... }
);