private void ensureRecordsIsMutable() {
            if (!records_.isModifiable()) {
                records_ = makeMutableCopy(records_);
            }
            bitField0_ |= 0x00000100;
        }
<code>optional int64 recipient_id = 8;</code>

@return This builder for chaining.
turms-server-common/src/main/java/im/turms/server/common/access/client/dto/model/message/Message.java