of static method
Reads the header of request, or null when there is none.
Implementation
static Authorization? of(Request request) {
final raw = RequestParts.of(request).headers['authorization'];
if (raw == null) return null;
final separator = raw.indexOf(' ');
if (separator < 1) return Authorization(raw.toLowerCase(), '');
return Authorization(
raw.substring(0, separator).toLowerCase(),
raw.substring(separator + 1).trim(),
);
}