OptionalinternalThe object containing the message data.
OptionalrecipientA list of person IDs to send the message to. The message is visible only to the specified recipients. If not set, the message is sent to all participants of the conversation.
OptionalreplyThe ID of the message that this message is replying to. If empty, the message isn't treated as a reply.
Whether the message is an internal message, visible only to agents and not to visitors. Only honored when sending as an agent. Defaults to
falseif not set.