LFLiveKit推流外部输入源

• 设置初始化LFLiveSession时枚举用LFLiveInputMaskAll

    LFLiveInputMaskAll = (LFLiveInputMaskAudio | LFLiveInputMaskVideo),                 ///< outer input audio and video(method see pushVideo and pushAudio)

• 当外部输入源来时，调用

/** support outer input yuv or rgb video(set LFLiveCaptureTypeMask) .*/
- (void)pushVideo:(nullable CVPixelBufferRef)pixelBuffer;