message: Update infix function to return true instead of leaving it up to the caller.
diff: @@ -1024,10 +1024,11 @@ export class IntervalTree<T extends IInterval> implements IRBAugmentation<T, Aug
  }
  }
  - map(fn: (x:T)=>any) {
  + map(fn: (x:T)=>void) {
  let actions = <RBNodeActions<T, AugmentedIntervalNode>> {
  infix: (node) => {
  - return fn(node.key);
  + fn(node.key);
  + return true;
  },
  showStructure: true,
  };
  