NewReader returns a new Reader which can read from the input source after verifying the checksum.

NewWriter returns a new Writer which calculates and stores a CRC-32 checksum for the payload before writing to the underlying object.

Reader implements an io.ReadAt, reading from the input source after verifying the checksum.

Writer implements an io.WriteCloser, it calculates and stores a CRC-32 checksum for the payload before writing to the underlying object.