@Override
  public int read() throws IOException {
    if (position < streamSize) {
      ++position;
      return 0;
    } else {
      return -1;
    }
  }
Returns 'size' number of zero bytes when read from.
@param size The number of zero bytes to be returned.
@throws IOException
ambry-utils/src/main/java/com/github/ambry/utils/ZeroBytesInputStream.java