code: func ReadVarUint32(r io.Reader) (uint32, error) {
  	u64, err := ReadVarUint64(r)
  	if err != nil {
  		return 0, err
  	}
  	return uint32(u64), nil
  }
docs: // Copied rom http://dwarfstd.org/doc/Dwarf3.pdf.
  // ReadVarUint32 tries to read a uint32 from r.