Function start_call 

pub fn start_call(
    registry: &TriggerRegistry,
    writer: &dyn GraphWriter,
    args: &[Value],
) -> Result<Vec<ProcRow>>

apoc.trigger.start(databaseName, name) — un-pause a previously stopped trigger. Looks up the existing spec through the registry, sets paused = false, and re-emits the spec via the writer so the cluster commit replicates the unpause. Errors if the trigger doesn’t exist.