pub trait CupProxyInterface: Send + Sync {
type WriteResponseFut: Future<Output = Result<CupWriteResult, Error>> + Send;
type GetInfoResponseFut: Future<Output = Result<CupGetInfoResult, Error>> + Send;
// Required methods
fn write(&self, url: &PackageUrl, cup: &CupData) -> Self::WriteResponseFut;
fn get_info(&self, url: &PackageUrl) -> Self::GetInfoResponseFut;
}