async function syntheticAudio(text, outFile) {
    // Replace special characters with HTML Ampersand Character Codes
    // These codes prevent the API from confusing text with SSML tags
    // For example, '<' --> '&lt;' and '&' --> '&amp;'
    let escapedLines = text.replace(/&/g, '&amp;');
    escapedLines = escapedLines.replace(/"/g, '&quot;');
    escapedLines = escapedLines.replace(/</g, '&lt;');
    escapedLines = escapedLines.replace(/>/g, '&gt;');

    // Convert plaintext to SSML
    // Tag SSML so that there is a 2 second pause between each address
    const expandedNewline = escapedLines.replace(/\n/g, '\n<break time="2s"/>');
    const ssmlText = '<speak>' + expandedNewline + '</speak>';

    // Creates a client
    const client = new textToSpeech.TextToSpeechClient();

    // Constructs the request
    const request = {
      // Select the text to synthesize
      input: {ssml: ssmlText},
      // Select the language and SSML Voice Gender (optional)
      voice: {languageCode: 'en-US', ssmlGender: 'MALE'},
      // Select the type of audio encoding
      audioConfig: {audioEncoding: 'MP3'},
    };

    // Performs the Text-to-Speech request
    const [response] = await client.synthesizeSpeech(request);
    // Write the binary audio content to a local file
    const writeFile = util.promisify(fs.writeFile);
    await writeFile(outFile, response.audioContent, 'binary');
    console.log('Audio content written to file ' + outFile);
  }
Generates synthetic audio from plaintext tagged with SSML.

Given the name of a text file and an output file name, this function
tags the text in the text file with SSML. This function then
calls the Text-to-Speech API. The API returns a synthetic audio
version of the text, formatted according to the SSML commands. This
function saves the synthetic audio to the designated output file.

ARGS
text: String of plaintext
outFile: String name of file under which to save audio output
RETURNS
nothing