Derive Macro BoundaryKind 

#[derive(BoundaryKind)]
{
    // Attributes available to this derive:
    #[boundary_kind]
}

Derive the BoundaryKind trait for a struct or enum.

#[derive(Debug, Clone, BoundaryKind)]
pub enum InferBoundary {
    LowConfidence { confidence: f64, threshold: f64 },
    Hallucinated  { claim: String, evidence_score: f64 },
    OutOfDomain   { distance: f64 },
}

Use #[boundary_kind(crate_path = "crate")] when inside the origin crate itself.