docs: @Override
      public void remove(int idx) {
  		int i = Arrays.binarySearch(indices, 0, used, idx);
  		if (i < 0) {
  			throw new IllegalArgumentException("This map does not contain the key: " + idx);
  		}		
  		// Shift the values over.
  		System.arraycopy(indices, i+1, indices, i, used - i - 1);
  		System.arraycopy(values, i+1, values, i, used - i - 1);
  		used--;
  	}