Sets the function to be called when a proxy is requesting
authentication. Information on the proxy in use and the security
realm for the authentication are passed in the arguments host,
port 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
addProxyCredentials 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.
Source
set authenticateProxy(
Future<bool> f(String host, int port, String scheme, String realm));