pub type PJRT_Event_OnReadyCallback = Option<unsafe extern "C" fn(error: *mut PJRT_Error, user_arg: *mut c_void)>;
pub enum PJRT_Event_OnReadyCallback { None, Some(unsafe extern "C" fn(*mut PJRT_Error, *mut c_void)), }
No value.
Some value of type T.
T