fn update_parent_gas(&mut self, state: &VmLocalStateData<'_>, current_call: &mut Call) {
        let current = state.vm_local_state.callstack.current;
        let parent_gas = state
            .vm_local_state
            .callstack
            .inner
            .last()
            .map(|call| call.ergs_remaining + current.ergs_remaining)
            .unwrap_or(current.ergs_remaining) as u64;
        current_call.parent_gas = parent_gas;
    }
We use parent gas for property calculation of gas used in the trace.
This method updates parent gas for the current call.
core/lib/multivm/src/versions/vm_m6/oracles/tracer/call.rs