Function payload 

pub fn payload(
    raw: RawDoc,
    payload: Vec<(PayloadId, String, Value)>,
) -> Result<RawDoc, PayloadError>

Change the payload of the document, using the set of triples:

• PayloadId: the identifier for the document Payload
• String: the key within the Payload that is being updated
• json::Value: the value to update the Payload

Errors

This fails if one of the PayloadIds does not point to a JSON object as its value.