I'm using ffmpeg version 3.2.4. Had some issues with earlier versions, but not any problems so far with this version.
ffmpeg.exe -f lavfi -i anullsrc -rtsp_transport tcp -i rtsp://USER:PASS@IP:PORT/Streaming/Channels/101 -tune zerolatency -vcodec libx264 -pix_fmt + -c:v copy -c:a aac -strict experimental -f flv rtmp://a.rtmp.youtube.com/live2/SECRET