/// `payload` is passed through another layer of raw pointers as `&mut dyn Trait` is not
/// FFI-safe. `BoxMeUp` lazily performs allocation only when needed (this avoids allocations
/// when using the "abort" panic runtime).
/// `payload` is passed through another layer of raw pointers as `&mut dyn Trait` is not
/// FFI-safe. `BoxMeUp` lazily performs allocation only when needed (this avoids allocations
/// when using the "abort" panic runtime).