code: function ConnectionCosts(forward_dimension, backward_dimension) {
      this.forward_dimension = forward_dimension;
      this.backward_dimension = backward_dimension;
  
      // leading 2 integers for forward_dimension, backward_dimension, respectively
      this.buffer = new Int16Array(forward_dimension * backward_dimension + 2);
      this.buffer[0] = forward_dimension;
      this.buffer[1] = backward_dimension;
  }
docs: Connection costs matrix from cc.dat file.
  2 dimension matrix [forward_id][backward_id] -> cost
  @constructor
  @param {number} forward_dimension
  @param {number} backward_dimension