Method set_position

external/parallel_hashmap/btree.h:1163–1163

        slot_type *slot(size_type i)       { return &GetField<2>()[i]; }
        const slot_type *slot(size_type i) const { return &GetField<2>()[i]; }
        void set_position(field_type v)    { GetField<1>()[0] = v; }
        void set_start(field_type v)       { GetField<1>()[1] = v; }
        void set_count(field_type v)       { GetField<1>()[2] = v; }
        void set_max_count(field_type v)   { GetField<1>()[3] = v; }