authenticate property

void authenticate= (Future<bool> f(Uri url, String scheme, String realm))

Sets the function to be called when a site is requesting authentication. The URL requested and the security realm from the server are passed in the arguments url and realm.

The function returns a Future which should complete when the authentication has been resolved. If credentials cannot be provided the Future should complete with false. If credentials are available the function should add these using addCredentials before completing the Future with the value true.

If the Future completes with true the request will be retried using the updated credentials. Otherwise response processing will continue normally.

Implementation 

set authenticate(Future<bool> f(Uri url, String scheme, String realm));