code: func NewReader(r io.Reader) *Reader {
  	return &Reader{
  		r:       r,
  		decoded: make([]byte, maxUncompressedChunkLen),
  		buf:     make([]byte, MaxEncodedLen(maxUncompressedChunkLen)+checksumSize),
  	}
  }
docs: // NewReader returns a new Reader that decompresses from r, using the framing
  // format described at
  // https://code.google.com/p/snappy/source/browse/trunk/framing_format.txt