gistfile1.txt

 #[derive(Deserialize, Debug)]                                                                                                                                          
struct GDAXMsg {                                                                                                                                                        
    #[serde(rename="type")]                                                                                                                                             
    type_: MsgType,                                                                                                                                                     
    time: String,                                                                                                                                                       
    product_id: String,                                                                                                                                                 
    sequence: u32,                                                                                                                                                      
    order_id: Option<String>,                                                                                                                                           
    side: String,                                                                                                                                                      
}                
...
let gmsg: GDAXMsg = serde_json::from_str(payload_string).unwrap();                                                                                          
println!("{:?}", gmsg);