presto-spi/src/main/java/io/prestosql/spi/block/ByteArrayBlockBuilder.java/ByteArrayBlockBuilder/toString
class ByteArrayBlockBuilder:    @Override
    public String toString()
    {
        StringBuilder sb = new StringBuilder("ByteArrayBlockBuilder{");
        sb.append("positionCount=").append(getPositionCount());
        sb.append('}');
        return sb.toString();
    }