The message content payload
The registered message type identifier (e.g. 'RC:TxtMsg')
List of target user IDs for directed messages. Only these users will receive the message.
If true, suppress push notifications for this message
If true, this message will not update the channel's last message
If true, request read receipt for this message
Key-value metadata (expansion) to attach to the message
Push notification configuration for this message
Callback invoked when the message is initialized
Callback invoked when the message is sending
Combined message content
Parameters for sending a combined/forwarded message.