Function libevent_sys::event_once

pub unsafe extern "C" fn event_once(
    arg1: c_int,
    arg2: c_short,
    arg3: Option<unsafe extern "C" fn(arg1: c_int, arg2: c_short, arg3: *mut c_void)>,
    arg4: *mut c_void,
    arg5: *const timeval
) -> c_int