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