public function __construct($column_family, $buffer_size, $key_start, $key_finish, $row_count, $column_parent, $predicate, $read_consistency_level)
 {
     // The key_start will be packed during the first get_buffer call
     $this->key_start = $key_start;
     $this->key_finish = $column_family->pack_key($key_finish);
     parent::__construct($column_family, $buffer_size, $row_count, $key_start, $column_parent, $predicate, $read_consistency_level);
 }
 public function __construct($column_family, $index_clause, $buffer_size, $column_parent, $predicate, $read_consistency_level)
 {
     $this->index_clause = $index_clause;
     $row_count = $index_clause->count;
     $orig_start_key = $index_clause->start_key;
     parent::__construct($column_family, $buffer_size, $row_count, $orig_start_key, $column_parent, $predicate, $read_consistency_level);
 }