Function event_publisher 

pub fn event_publisher(
    target: &str,
    event: &str,
    unit_tables: &HashMap<String, UnitTable>,
    consumed: &[String],
) -> Result<String, Vec<String>>

#2052 review: the context that publishes event to target’s subscribers, resolved as the target’s from Events(E) header resolves E: the target’s own declaration, else the one context among those it consumes (consumed) that declares it. Err lists the candidates when there is no unique one (none, or several). A same-named event in a context the target does not consume is never a candidate.