Flutter与iOS原生通信方式

@interface ViewController ()<FlutterStreamHandler>
@property(strong, nonatomic) NSTimer *timer;
@property(strong, nonatomic) FlutterEngine *flutterEngine;
@property(strong, nonatomic) FlutterViewController *flutterVC;
@property(strong, nonatomic) FlutterBasicMessageChannel *basicMessageChannel;
@property(strong, nonatomic) FlutterEventChannel *eventChannel;
@property(copy, nonatomic) FlutterEventSink eventSink;
@end

- (FlutterEngine *)flutterEngine {
    if (!_flutterEngine) {
        FlutterEngine *engine = [[FlutterEngine alloc] init];
        if (engine.run) {
            _flutterEngine = engine;
        }
    }
    return _flutterEngine;
}
- (FlutterViewController *)flutterVC {
    if (!_flutterVC) {
        _flutterVC = [[FlutterViewController alloc] initWithEngine:self.flutterEngine nibName:nil bundle:nil];
    }
    return _flutterVC;
}
- (FlutterBasicMessageChannel *)basicMessageChannel {
    if (!_basicMessageChannel) {
        //注册FlutterBasicMessageChannel - 并指定名称messageChannelName为basicMessageChannel
        _basicMessageChannel = [FlutterBasicMessageChannel messageChannelWithName:@"basicMessageChannel" binaryMessenger:self.flutterVC.binaryMessenger];
        //监听Flutter发来的消息 - Flutter调用OC回调监听
        [_basicMessageChannel setMessageHandler:^(id  _Nullable message, FlutterReply _Nonnull callback) {
            NSLog(@"OC收到Flutter的FlutterBasicMessageChannel - %@", message);
        }];
    }
    return _basicMessageChannel;
}
- (FlutterEventChannel *)eventChannel {
    if (!_eventChannel) {
        _eventChannel = [FlutterEventChannel eventChannelWithName:@"eventChannel" binaryMessenger:self.flutterVC.binaryMessenger];
        [_eventChannel setStreamHandler:self];
    }
    return _eventChannel;
}

flutter: 消息内容: OC通过EventChannel向Flutter发送消息(OC参数类型是id), Flutter收到消息数据类型: String