tracing

type Span interface {
	End()
	SetAttribute(key string, value any)
	Context() SpanContext
	IsEnded() bool
}

type SpanContext struct {
	TraceID, SpanID, ParentSpanID string
	Start, End                    time.Time
}

type Tracer interface {
	StartSpan(ctx context.Context, name string) (context.Context, Span)
	Noop() bool
}