/** Registers a metadata observer.
*
* You need to implement the MetadataObserver class and specify the metadata type in this method. A successful call of this method triggers the {@link agora_gaming_rtc.MetadataObserver.OnGetMaxMetadataSizeHandler OnGetMaxMetadataSizeHandler} callback. This method enables you to add synchronized metadata in the video stream for more diversified live broadcast interactions, such as sending shopping links, digital coupons, and online quizzes.
*
* @note
* - Call this method before the {@link agora_gaming_rtc.IRtcEngine.JoinChannelByKey JoinChannelByKey} method.
* - This method applies to the Live-broadcast channel profile.
*
* @param metaDataType See {@link agora_gaming_rtc.METADATA_TYPE METADATA_TYPE}. The SDK supports `VIDEO_METADATA(0)` only for now.
*
* @return
* - 0: Success.
* - < 0: Failure.
*/
public override int RegisterMediaMetadataObserver(METADATA_TYPE metaDataType)
{
if (_irtcEngine == null)
{
return((int)ERROR_CODE.ERROR_NOT_INIT_ENGINE);
}
IRtcEngineNative.initEventOnMetaDataCallback(OnMediaMetaDataReceivedCallback, OnReadyToSendMetadataCallback, OnGetMaxMetadataSizeCallback);
return(IRtcEngineNative.registerMediaMetadataObserver((int)metaDataType));
}