Trait Callee
pub trait Callee: Send + Sync {
type Error: Debug;
// Required method
fn on_call<'life0, 'async_trait>(
&'life0 self,
header: CallHeader,
from: NodeID,
input: RemoteObj,
) -> Pin<Box<dyn Future<Output = Result<RemoteObj, Self::Error>> + Send + 'async_trait>>
where Self: 'async_trait,
'life0: 'async_trait;
}