removeAllCachedResponses不能完全清除緩存嗎？

[[NSURLCache sharedURLCache]removeAllCachedResponses]；

然後檢查緩存是否被清空:

NSInteger size integer =[[NSURLCache sharedURLCache]currentDiskUsage]；

float size inmb = size integer/(1024.0 f * 1024.0 f)；