IRTCCustomAudioTrack

virtual StatusCode pushAudioFrame(int stmtype, unsigned char* buf, int buf_len, long ts) = 0;

// 推送 OPUS 音频帧
IRTCCustomAudioTrack* track = nullptr;
engine->getCustomAudioTrack("my_custom_audio", &track);
track->pushAudioFrame(0x5355504F, audioData, audioSize, timestamp);