Enum DispatchOutcome 

pub enum DispatchOutcome {
    OneShot(Result<Value, WireError>),
    Stream(Box<dyn EventStream + Send>),
}

What dispatch returns. One-shot verbs (ping, stats, …) produce a single result/error frame; streaming verbs (tail_flow) produce a sequence of Event frames terminated by an End frame.

Variants

OneShot(Result<Value, WireError>)

One-shot reply: a single JSON value or a structured error.

Stream(Box<dyn EventStream + Send>)

Streaming reply: each call to next_event yields the next Event payload, or None to terminate with an End frame.