Optional type
type: "Introductory" | "Announcement" | "ConnectingMessage" | "ConnectingAudio" | "Voicemail" | "Unavailable" | "InterruptPrompt" | "HoldMusic" | "Custom" | "Company" | "BlockedCallersSpecific" | "BlockedCallersAll" | "BlockedNoCallerId" | "BlockedPayPhones" | "StartRecording" | "StopRecording" | "AutomaticRecording"
Type of a greeting, specifying the case when the greeting is played. See Greeting Types = ['Introductory', 'Announcement', 'ConnectingMessage', 'ConnectingAudio', 'Voicemail', 'Unavailable', 'InterruptPrompt', 'HoldMusic']