Function unpack_postgres 

pub async fn unpack_postgres(
    zip_file_path: &Path,
    cache_dir: &Path,
) -> Result<()>

Unpacks the PostgreSQL binaries ZIP/JAR into cache_dir.

Spawns a blocking task that opens zip_file_path, finds the .txz entry (XZ-compressed tarball), decompresses it, and extracts the tar archive into cache_dir.

Arguments

• zip_file_path — Path to the downloaded JAR file.
• cache_dir — Destination directory for the extracted binaries.

Errors

Returns Error::ReadFileError if the ZIP file cannot be opened. Returns Error::InvalidPgPackage if the archive is malformed or an entry cannot be read. Returns Error::UnpackFailure if XZ decompression or tar extraction fails. Returns Error::PgError if the blocking task panics or cannot be joined.