code: @Override
  	public BitStore range(int from, int to) {
  		return store.range(from, to).immutableView();
  	}
docs: /*
  @Override
  public Op and() {
  return IMM_AND;
  }
  
  @Override
  public Op or() {
  return IMM_OR;
  }
  
  @Override
  public Op xor() {
  return IMM_XOR;
  }
  
  @Override
  public Op set() {
  return IMM_SET;
  }