Format with "%v" instead of "%d"

[lwlwilliam]

The Data field of type DataTransferRequest is defined as interface{}.

In addition, I see that the data keys in ocppj1.6's DataTransfer.json and DataTransferResponse.json are both string types. Do I need to change the Data fields of the DataTransferRequest and DataTransferConfirmation types to the string type?

[lorenzodonini]

Hey and thanks for the contribution!

The data field is defined as interface to leave the implementation completely open. Enforcing a string type would force everyone to embed a json string within a string field (which is already inside a json), which is imo crazy. The specs for OCPP v2.0.1 define this field as anyType btw, since that's how it was intended in the first place.

That being said, the field can obviously be used as a string, if needed. Check out data_transfer_test.go for an example.