Cause   error  // Optional, lower level error cause.
}

func (e Error) Error() string {
	if e.Cause == nil {
		return e.Err
	}
	return fmt.Sprintf("%s: %v", e.Err, e.Cause)
}

func errKeyCreationFailed(err error) Error {
	return Error{
		Code:    http.StatusInternalServerError,
		APICode: "kms:KeyCreationFailed",
		Err:     "failed to create KMS key",
		Cause:   err,
	}
}

	if err := c.client.CreateKey(ctx, req.Name); err != nil {
		if errors.Is(err, kes.ErrKeyExists) {
			return ErrKeyExists
		}
		if errors.Is(err, kes.ErrNotAllowed) {
			return ErrPermission
		}
		return errKeyCreationFailed(err)
	}
	return nil
}

// DeleteKey deletes a key at the KMS with the given key ID.
// Please note that is a dangerous operation.

		Name:    req.Name,
	}); err != nil {
		if errors.Is(err, kms.ErrKeyExists) {
			return ErrKeyExists
		}
		if errors.Is(err, kms.ErrPermission) {
			return ErrPermission
		}
		return errKeyCreationFailed(err)
	}
	return nil
}

func (c *kmsConn) GenerateKey(ctx context.Context, req *GenerateKeyRequest) (DEK, error) {
	aad, err := req.AssociatedData.MarshalText()
	if err != nil {
		return DEK{}, err