Function on_start_mac 

pub fn on_start_mac<H, S, E>(
    handler: H,
) -> impl Handler<S, E, Output = H::Output>
where
    H: Handler<S, StartMacArgs>,
    E: AsEvent<StartMacArgs>,

Filters WlantapPhyEvents to StartMacArgs.

The composed event handler must accept StartMacArgs and is only invoked when such an event is received by the filter. Otherwise, the filter returns Handled::Unmatched.