pub trait Service {
type Stream: Stream<Item = Result<MessagePack, Status>> + Send;
// Required method
fn call<'life0, 'async_trait>(
&'life0 self,
fn_name: String,
args: Option<MessagePack>,
) -> Pin<Box<dyn Future<Output = Result<Self::Stream, Status>> + Send + 'async_trait>>
where Self: 'async_trait,
'life0: 'async_trait;
}