symbol
The symbolSortKey property
Sorts features in ascending order based on this value. Features with lower sort keys are drawn and placed first. When {@link PropertyFactory#iconAllowOverlap} or {@link PropertyFactory#textAllowOverlap} is false, features with a lower sort key will have priority during placement. When {@link PropertyFactory#iconAllowOverlap} or {@link PropertyFactory#textAllowOverlap} is set to true, features with a higher sort key will overlap over features with a lower sort key.