Function sample_url 

pub fn sample_url<AnyPath0>(path: AnyPath0) -> Result<String, Box<BedErrorPlus>>
where
    AnyPath0: AsRef<Path>,

Returns the cloud location of a sample file as a URL string.

Behind the scenes, the “cloud location” will actually be local. If necessary, the file will be downloaded. A SHA256 hash is used to verify that the file is correct. The file will be in a directory determined by environment variable BED_READER_DATA_DIR. If that environment variable is not set, a cache folder, appropriate to the OS, will be used.