code: func EncodeFloat(b []byte, v float64) []byte {
  	u := encodeFloatToCmpUint64(v)
  	return EncodeUint(b, u)
  }
docs: // EncodeFloat encodes a float v into a byte slice which can be sorted lexicographically later.
  // EncodeFloat guarantees that the encoded value is in ascending order for comparison.