def __init__(self, device_id, record, ref):
self.device_id = device_id<EOL>self.record = record<EOL>self.ref = ref<EOL>self.success = False<EOL>
Constructs VIF

        `device_id` and `mac_address` should be strings if they will later be
        compared to decoded VIF instances (via from_string).

        `ref` is the OpaqueRef string for the vif as returned from xenapi.