# Functions
DownloadAndExtract downloads the specified archive uri (or uses the provided overrideFile, if a non-empty value) while validating its checksum with the provided sha256sum, and extracts its contents to extractDir that must be.
NewDownloader builds a new Downloader.
NewFileFetcher returns a local file reader.
NewSha256Verifier creates a Verifier that tests against the given hash.
# Structs
Downloader is responsible for fetching, verifying and extracting a binary.
HTTPFetcher is used to get a file from a http:// or https:// schema path.