Function read_central_directory_from 

pub fn read_central_directory_from<R: Read + Seek>(
    source: &mut R,
) -> Result<Vec<EntryLocation>, ZipError>

Parse the ZIP Central Directory from a Read + Seek source without loading the whole file into memory.

Seeks to the file tail to locate the EOCD, reads only the Central Directory bytes, then walks the entries. Suitable for large ZIPs where loading the full file would be wasteful.