Function decode_payload 

pub fn decode_payload<T>(type_id: &str, payload: &[u8]) -> Result<T, Error>
where
    T: DeserializeOwned,

A T from the payload of an action of type type_id, like decode_json: a group written with what its members share once (crate::group_form) reads as the list of them.

Errors

Why the payload is not a T.