// DummyDataGen returns a reader that repeats the bytes in `alphabets`
// upto the desired length.
type DummyDataGen struct {
	b           []byte
	idx, length int64
}

// NewDummyDataGen returns a ReadSeeker over the first `totalLength`
// bytes from the infinite stream consisting of repeated
// concatenations of `alphabets`.
//
// The skipOffset (generally = 0) can be used to skip a given number