Function load_visa_library_from_path 

pub fn load_visa_library_from_path<P: AsRef<OsStr>>(
    path: P,
) -> Result<(), Error>

Manually load the VISA library from a custom path.

Returns Ok(()) if the library was loaded successfully, or Err if loading fails.

The first successful load wins: if the library was already loaded — including an auto-load triggered by an earlier VISA call, or a load from a different path — this is a no-op that returns Ok(()) and the original instance is kept. Call this (or load_visa_library) before any other VISA function to be sure your path is the one used.