public Builder setDeleteGroupIndex(int value) {
            copyOnWrite();
            instance.setDeleteGroupIndex(value);
            return this;
        }
<code>optional int32 delete_group_index = 4;</code>

@param value The deleteGroupIndex to set.
@return This builder for chaining.
turms-client-kotlin/src/main/java/im/turms/client/model/proto/request/user/relationship/UpdateRelationshipRequest.java