Enum Step 

pub enum Step {
    CallModel(Box<CallModel>),
    CallDecision(Box<CallDecision>),
    Done(Box<RoutingOutcome>),
}

Work requests and the terminal outcome of Algorithm::run_stream. Each call carries its own reply channel, so the host can execute calls concurrently.

Variants

CallModel(Box<CallModel>)

The algorithm needs this model call performed. The host serves it and fulfills it with CallModel::respond. Boxed: it is by far the largest variant.

CallDecision(Box<CallDecision>)

The host fulfills this decision call with CallDecision::respond.

Done(Box<RoutingOutcome>)

The algorithm finished with its routing outcome — the last step of a run.