I dunno , if this feature exists yet. hence i'm gonna enquire first and then request. my specific usecase is that i have all of my bussiness logic already setup , i'm taking requests from my clients through various ways, and i'm processing them on my backend and then outputing text. what i want now, is the ability to send this text to VAPI and "VAPI to send audio back to my server" or "or to my client directly". so i wanna trigger/initiate a call on vapi , not via user voice but via user text. can i do this?