Synthesize speech synchronously.

This endpoint returns binary 16-bit wav data with a sample rate of 22050 Hz.

Voice can be specified by providing either voice + model_type, or
voicemodel_uuid.

Pace, duration, and pitch are only supported for voices
that support these controls (a very small subset of voices).

You can check if a given voice supports controls by querying /voice-data or
/voices//detail and looking at the controls boolean in
the reponse.