origin property
Returns the origin of the URI in the form scheme://host:port for the schemes http and https.
It is an error if the scheme is not "http" or "https", or if the host name is missing or empty.
See: https://www.w3.org/TR/2011/WD-html5-20110405/origin-0.html#origin
Implementation
@override
String get origin => uri.origin;