presto-main/src/main/java/io/prestosql/operator/aggregation/state/TriStateBooleanStateSerializer.java/TriStateBooleanStateSerializer/deserialize
class TriStateBooleanStateSerializer:    @Override
    public void deserialize(Block block, int index, TriStateBooleanState state)
    {
        state.setByte(BOOLEAN.getBoolean(block, index) ? TRUE_VALUE : FALSE_VALUE);
    }