Hash testing format

This muxer computes and prints a cryptographic hash of all the input audio and video frames. To compute the SHA-256 hash of the input converted to raw audio and video, and store it in the file hash.sha256:

string output = Path.Combine("C:", "Temp", "hash.sha256");
string inputVideoPath = Path.Combine("C:", "Temp", "input.mkv");

var mediaInfo = await FFmpeg.GetMediaInfo(inputVideoPath);

var conversionResult = await FFmpeg.Conversions.New()