Merge "audio: Add missing throttling and error handling to 'out_' thread" into main

    const size_t bufferSize = mBufferSizeFrames * mFrameSizeBytes;

    std::vector<char> buffer(bufferSize);

    while (mIoThreadIsRunning) {

        ssize_t framesRead = mSources[idx]->read(&buffer[0], mBufferSizeFrames);

        if (framesRead > 0) {

        ssize_t framesReadOrError = mSources[idx]->read(&buffer[0], mBufferSizeFrames);

        if (framesReadOrError > 0) {

            int ret = proxy_write_with_retries(mAlsaDeviceProxies[idx].get(), &buffer[0],

                                               framesRead * mFrameSizeBytes, mReadWriteRetries);

                                               framesReadOrError * mFrameSizeBytes,

                                               mReadWriteRetries);

            // Errors when the stream is being stopped are expected.

            LOG_IF(WARNING, ret != 0 && mIoThreadIsRunning)

                    << __func__ << "[" << idx << "]: Error writing into ALSA: " << ret;

        } else if (framesReadOrError == 0) {

            // MonoPipeReader does not have a blocking read, while use of std::condition_variable

            // requires use of a mutex. For now, just do a 1ms sleep. Consider using a different

            // pipe / ring buffer mechanism.

            if (mIoThreadIsRunning) usleep(1000);

        } else {

            LOG(WARNING) << __func__ << "[" << idx

                         << "]: Error while reading from the pipe: " << framesReadOrError;

        }

    }

}