HashedFiles constructor
The files in dir, each named <sha256>.<ext>.
Implementation
HashedFiles(String dir, {this.ext = 'bin'})
: dir = dir.replaceAll(r'\', '/') {
if (!RegExp(r'^[a-z0-9]{1,8}$').hasMatch(ext)) {
throw ArgumentError.value(ext, 'ext', 'Not a file extension.');
}
}