description

# TimelineTask constructor Null safety

TimelineTask(

1. {TimelineTask? parent,
2. String? filterKey}

)

Create a task. The task ID will be set by the system.

If `parent` is provided, the parent's task ID is provided as argument 'parentId' when start is called. In DevTools, this argument will result in this TimelineTask being linked to the `parent` TimelineTask.

If `filterKey` is provided, a property named `filterKey` will be inserted into the arguments of each event associated with this task. The `filterKey` will be set to the value of `filterKey`.

## Implementation

    TimelineTask({TimelineTask? parent, String? filterKey})
        : _parent = parent,
          _filterKey = filterKey,
          _taskId = _getNextAsyncId() {}