errz

type ErrReporter interface {
	// HandleProcessingError can be used to handle errors occurring while processing a request.
	// If err is a (or wraps a) errz.UserError, it might be handled specially.
	HandleProcessingError(ctx context.Context, log *zap.Logger, msg string, err error)
}

type UserError struct {
	// Message is a textual description of what's wrong.
	// Must be suitable to show to the user.
	Message string
	// Cause optionally holds an underlying error.
	Cause error
}