SynthesisInput
import type { SynthesisInput } from "https://googleapis.deno.dev/v1/texttospeech:v1.ts";Contains text input to be synthesized. Either text or ssml must be
supplied. Supplying both or neither returns google.rpc.Code.INVALID_ARGUMENT.
The input size is limited to 5000 bytes.
interface SynthesisInput {
ssml?: string;
text?: string;
}