pub trait DeviceExtraProxyInterface: Send + Sync {
type GetCredentialResponseFut: Future<Output = Result<Option<Box<Credential>>, Error>> + Send;
type WatchIdentityResponseFut: Future<Output = Result<Identity, Error>> + Send;
type GetCurrentMacAddressResponseFut: Future<Output = Result<MacAddress, Error>> + Send;
// Required methods
fn get_credential(&self) -> Self::GetCredentialResponseFut;
fn watch_identity(&self) -> Self::WatchIdentityResponseFut;
fn get_current_mac_address(&self) -> Self::GetCurrentMacAddressResponseFut;
}