public Task UpdateAsync()
{
if (_updateTask != null)
{
return(_updateTask);
}
var checksum = EnabledSources.Aggregate(0L, (current, source) => (current * 397) ^ source.ChangeId);
if (checksum == _previousChecksum)
{
return(Task.Delay(0));
}
_previousChecksum = checksum;
return(_updateTask = UpdateAsyncInner());
}