flutter:
    sdk: flutter
  flutter_bloc: ^0.19.0
  chopper: ^2.4.2
  built_value: ^6.7.0
  kiwi: ^0.2.0
  shared_preferences: ^0.5.3+4
  url_launcher: ^5.1.1
  event_bus: ^1.1.0
  flutter_sms: ^1.0.1
  rxdart: ^0.22.0
  rxbus: ^0.0.2`

After adding rxbus I am getting the following error:

Running "flutter pub get" in example_project...                    

Because example_project depends on rxbus ^0.0.2 which depends 
on rxdart ^0.20.0, rxdart ^0.20.0 is required.
So, because example_project depends on rxdart ^0.22.0, 
version solving failed.
pub get failed (1)
Process finished with exit code 1

I guess you need to upgrade your RxDart version to latest.

static void destroy({tag}) {
_list.forEach((rxBus) {
if (tag != null && tag != _DEFAULT_IDENTIFIER && rxBus.tag == tag) {
rxBus.subject.close();
_list.remove(rxBus);
} else if ((tag == null || tag == _DEFAULT_IDENTIFIER) && rxBus.tag == _DEFAULT_IDENTIFIER) {
rxBus.subject.close();
_list.remove(rxBus);
}
});
}
在进行迭代循环时试图删除list中内容，导致异常抛出，建议的修改方案如：
///事件关闭
static void destroy({tag}) {
var toRemove = [];
_list.forEach((rxBus) {
if (tag != null && tag != _DEFAULT_IDENTIFIER && rxBus.tag == tag) {
rxBus.subject.close();
toRemove.add(rxBus);
} else if ((tag == null || tag == _DEFAULT_IDENTIFIER) &&
rxBus.tag == _DEFAULT_IDENTIFIER) {
rxBus.subject.close();
toRemove.add(rxBus);
}
});
toRemove.forEach((rxBus) {
_list.remove(rxBus);
});
}