pub type PFE_EXPORT_FUNC = Option<unsafe extern "C" fn(pbData: PBYTE, pvCallbackContext: PVOID, ulLength: ULONG) -> DWORD>;
pub enum PFE_EXPORT_FUNC { None, Some(unsafe extern "C" fn(*mut u8, *mut c_void, u32) -> u32), }
No value.
Some value of type T.
T