startSync method Null safety

void startSync (
  1. String name,
  2. {Map? arguments,
  3. Flow? flow}

Start a synchronous operation labeled name. Optionally takes a Map of arguments. This slice may also optionally be associated with a Flow event. This operation must be finished before returning to the event queue.


static void startSync(String name, {Map? arguments, Flow? flow}) {
  if (!_hasTimeline) return;
  // TODO: When NNBD is complete, delete the following line.
  ArgumentError.checkNotNull(name, 'name');
  if (!_isDartStreamEnabled()) {
    // Push a null onto the stack and return.
  var block = new _SyncBlock._(name);
  if (arguments != null) {
    block._arguments = arguments;
  if (flow != null) {
    block.flow = flow;