docs: private Chunk chunkD() {
      if (H2O.SINGLE_PRECISION) {
        final byte[] bs = MemoryManager.malloc1(_len * 4, true);
        int j = 0;
        for (int i = 0; i < _len; ++i) {
          float f = 0;
          if (_id == null || _id.length == 0 || (j < _id.length && _id[j] == i)) {
            f = _ds != null ? (float)_ds[j] : (isNA2(j) || isEnum(j)) ? Float.NaN : (float)(_ls[j] * PrettyPrint.pow10(_xs[j]));
            ++j;
          }
          UDP.set4f(bs, 4 * i, f);
        }
        assert j == _sparseLen : "j = " + j + ", _sparseLen = " + _sparseLen;
        return new C4FChunk(bs);
      } else {
        final byte[] bs = MemoryManager.malloc1(_len * 8, true);
        int j = 0;
        for (int i = 0; i < _len; ++i) {
          double d = 0;
          if (_id == null || _id.length == 0 || (j < _id.length && _id[j] == i)) {
            d = _ds != null ? _ds[j] : (isNA2(j) || isEnum(j)) ? Double.NaN : _ls[j] * PrettyPrint.pow10(_xs[j]);
            ++j;
          }
          UDP.set8d(bs, 8 * i, d);
        }
        assert j == _sparseLen : "j = " + j + ", _sparseLen = " + _sparseLen;
        return new C8DChunk(bs);
      }
    }