The caller, resolved to the SAME canonical id their messages carry as
senderId (the identity-stability contract applies to calls too).
Transport status, e.g. WhatsApp offer / ringing / reject / timeout / terminate.
OptionalchatThe chat the call belongs to: the group for a group call. Omitted → the DM
with the caller (from).
Optionalistrue when chatId is a group (a group call). Provider-set, like ChatInfo.isGroup.
Optionalistrue for a video call, when the transport says so.
Optionalofflinetrue when the notification was delivered late (e.g. replayed after the bot
reconnected) rather than while the call was ringing.
An inbound call notification. Transports may emit several per call (one per status update) with the same
id.