envelope

type Config[P shared.Param] struct {
	Storage storage.IStorage

	Adapter string
	Status  string

	ID       string
	Target   string
	HookData any

	// ResolveTarget, when set, computes the target after params are merged and
	// before the hooks run — inside the span, so a resolution failure is traced
	// like any other. Its result replaces Target for both hooks and is passed to
	// the body.
	//
	// It exists because the adapters differ on this: some have a fixed target,
	// while the SQL adapters derive one from the caller's argument and their own
	// configured default via shared.TargetName. Resolving before Run would move
	// the failure outside the span, and resolving inside body would run the
	// pre-hook too early and hand it an unresolved target. Both are behaviour
	// changes, so the resolution point has to sit here.
	ResolveTarget func() (string, error)

	Param      *P
	Options    []storage.Func[*P]
	NewParams  func() (*P, error)
	RequiresID bool

	SuccessCounter *expvar.Int
	FailureCounter *expvar.Int
}

type Result[R any] struct {
	Value        R
	PostHookData any
}

type Void struct{}