Workaround: requestPriority() is one-way

        data.writeInt32(pid);

        data.writeInt32(tid);

        data.writeInt32(prio);

        remote()->transact(REQUEST_PRIORITY_TRANSACTION, data, &reply);

        remote()->transact(REQUEST_PRIORITY_TRANSACTION, data, &reply, IBinder::FLAG_ONEWAY);

        // fail on exception

        if (reply.readExceptionCode() != 0) return -1;

        return reply.readInt32();