disk       StorageAPI
	volume     string
	filePath   string
	verifier   *BitrotVerifier // Holds the bit-rot info
	tillOffset int64           // Affects the length of data requested in disk.ReadFile depending on Read()'s offset
	buf        []byte          // Holds bit-rot verified data
}

func (b *wholeBitrotReader) ReadAt(buf []byte, offset int64) (n int, err error) {
	if b.buf == nil {
		b.buf = make([]byte, b.tillOffset-offset)