presto-thrift-api/src/main/java/io/prestosql/plugin/thrift/api/datatypes/PrestoThriftVarchar.java/PrestoThriftVarchar/fromBlock
class PrestoThriftVarchar:    public static PrestoThriftBlock fromBlock(Block block, Type type)
    {
        return fromSliceBasedBlock(block, type, (nulls, sizes, bytes) -> varcharData(new PrestoThriftVarchar(nulls, sizes, bytes)));
    }