_getHubSizes() {
    const hubSizes = {};
    const nodeIds = this.body.nodeIndices;

    forEach(nodeIds, (nodeId) => {
      const node = this.body.nodes[nodeId];
      const hubSize = this._getActiveEdges(node).length;
      hubSizes[hubSize] = true;
    });

    // Make an array of the size sorted descending
    const result = [];
    forEach(hubSizes, (size) => {
      result.push(Number(size));
    });

    result.sort(function (a, b) {
      return b - a;
    });

    return result;
  }
Get the hubsizes for all active nodes.
@returns {number}
@private