presto-spi/src/main/java/io/prestosql/spi/block/VariableWidthBlockBuilder.java/VariableWidthBlockBuilder/closeEntry
class VariableWidthBlockBuilder:    @Override
    public BlockBuilder closeEntry()
    {
        entryAdded(currentEntrySize, false);
        currentEntrySize = 0;
        return this;
    }