header method
Implementation
String header(Uri uri) {
_cookies.removeWhere((key, value) =>
value.expires != null && !value.expires!.isAfter(_clock()));
final matching = _cookies.values
.where((value) =>
value.host == uri.host &&
(!value.cookie.secure || uri.scheme == 'https') &&
(uri.path == value.path ||
uri.path.startsWith(
value.path.endsWith('/') ? value.path : '${value.path}/')))
.toList()
..sort((a, b) => b.path.length.compareTo(a.path.length));
return matching
.map((value) => '${value.cookie.name}=${value.cookie.value}')
.join('; ');
}