isSilent property
Determines whether to send a message without updating some of the channel properties. If set to true, the channel's last_message is updated only for the sender while its unread_message_count remains unchanged for all channel members. Also, a push notification isn't sent to the users who receive the message. If the message is sent to a hidden channel, the channel still remains hidden. (Default: false)
Implementation
final bool isSilent;