Log
use fuel_types::ContractId;
pub struct Log {
    pub contract_id: ContractId,
    pub ra: u64,
    pub rb: u64,
}- A Logreceipt is generated when callinglog()on a non-reference types in a Sway contracts.- Specifically bool,u8,u16,u32, andu64.
 
- Specifically 
- The rafield includes the value being logged whilerbmay include a non-zero value representing a unique ID for theloginstance.
- Read more about Login the Fuel protocol ABI spec