playerFactoryOverride property
可测试性注入点:允许测试时替换播放器创建逻辑
Testability injection point: allows tests to replace player creation.
设置后,_initializePlayer 将使用此工厂而非
FlutterAliPlayerFactory.createAliPlayer。
测试结束后应置为 null 以恢复默认行为。
Implementation
@visibleForTesting
static FlutterAliplayer Function()? playerFactoryOverride;