code: public static byte[] hashToBytes(final double datum, final long seed) {
      final double d = (datum == 0.0) ? 0.0 : datum; //canonicalize -0.0, 0.0
      final long[] data = { Double.doubleToLongBits(d) }; //canonicalize all NaN forms
      return toByteArray(hash(data, seed));
    }
docs: Hash a double and long seed.
  
  @param datum the input double
  @param seed A long valued seed.
  @return The 128-bit hash as a byte[16] in Big Endian order from 2 64-bit longs.