private @Nullable ExecutionNode getOrMaybeCreateParentNode(@NotNull BuildEvent event,
                                                             @NotNull Set<? super ExecutionNode> structureChanged) {
    ExecutionNode parentNode = event.getParentId() == null ? null : nodesMap.get(event.getParentId());
    if (event instanceof MessageEvent) {
      parentNode = createMessageParentNodes((MessageEvent)event, parentNode);
      addIfNotNull(structureChanged, parentNode);
    }
    return parentNode;
  }
private @Nullable ExecutionNode getOrMaybeCreateParentNode(@NotNull BuildEvent event,
                                                             @NotNull Set<? super ExecutionNode> structureChanged)