ReadonlyactionReadonlynameName of the Custom Field to add, update, or remove.
Optional ReadonlyvalueIf value is absent or null, this field will be removed if it exists.
Trying to remove a field that does not exist will fail with an InvalidOperation error.
If value is provided, it is set for the field defined by name.
Adding a Custom Field to a PaymentMethod generates the PaymentMethodCustomFieldAdded Message, removing one generates the PaymentMethodCustomFieldRemoved Message, and updating an existing one generates the PaymentMethodCustomFieldChanged Message.