Function send_sms_async 

pub unsafe extern "C" fn send_sms_async(
    handle: Handle,
    sms_info: *mut Sms,
    id: *mut c_int,
) -> c_int

Available on non-ag35 only.

Send sms asynchronously, you just need to fill format/src_addr/sms_data_len/sms_data, if format is UCS2, the data should be Unicode-BE format.