Preloading TTS Files

1. Set up the TTS Preload settings
   a. Navigate to Assets > Create > Voice SDK > TTS Preload Settings to generate a TTS Preload Settings asset.
   Note: A TTS Preload Settings asset can only be used in a scene with a TTSService. The service itself should automatically be found and linked at the top of the Inspector window.
   b. Select the generated asset and view in the Inspector window. Preload or delete clips in the TTS cache.
   
2. Add any voices and phrases desired.
   a. Click Add Voice.
   b. Expand the voice displayed and for Voice ID, select the voice you want to use from the list.
   c. Click Add Phrase.
   d. Expand Phrases and enter the Phrase and Clip ID as appropriate.
   e. Add additional voices or phrases as needed.
   
3. To speed the import of TTS preload data, click Import JSON to load a JSON file with phrases. The file itself contains dictionaries which have arrays of phrases for each voice.
   For more complex data imports, use the TTSPreloadUtility.ImportData method to import a dictionary of phrases for each voice directly into a TTSPreloadSettings file.
   Note: Importing data does not allow for duplication of the same phrase. Any duplicated phrase using the same voice is ignored.
   
4. After all phrases have been imported into a TTSPreloadSetting asset, click Preload Cache. This loads all TTS files into the TTS StreamingAssets directory.
5. To remove the files from the TTS preload disk cache, click Delete Cache.
6. To update the download state for each clip, click Refresh Data.