pub trait PayloadStreamProxyInterface: Send + Sync {
type RegisterVmoResponseFut: Future<Output = Result<i32, Error>> + Send;
type ReadDataResponseFut: Future<Output = Result<ReadResult, Error>> + Send;
// Required methods
fn register_vmo(&self, vmo: Vmo) -> Self::RegisterVmoResponseFut;
fn read_data(&self) -> Self::ReadDataResponseFut;
}