TarGz tars and gzips "src", rooted at the last directory, into the file named "dst" Ex If "src" includes "/tmp/envoy/bin" and "/tmp/build/bin".

Untar unarchives the compressed "src" which is either a "tar.xz" or "tar.gz" stream.

UntarAndVerify is like Untar, except it errors if the stream has a different signature than the given SHA-256.