Like DBusProxy.sync but takes a BusType instead of a DBusConnection.
DBusProxy is used in this example.
| bus_type |
A BusType. |
| flags |
Flags used when constructing the proxy. |
| info |
A DBusInterfaceInfo specifying the minimal interface that |
| name |
A bus name (well-known or unique). |
| object_path |
An object path. |
| interface_name |
A D-Bus interface name. |
| cancellable |
A Cancellable or null. |