I am trying to send some messages using the Rocket.Chat notifier plugin that contains special characters such as ampersands. I use the Jenkins declarative pipeline syntax for this and the below snippet.

rocketSend(
    channel: 'notification-channel',
    message: "[Click here](http://www.example.com?param1=value1&param2=value2&param3=value3)",
    rawMessage: true
)

However, despite having set rawMessage: true, the messages that are received have all & characters HTML escaped into & causing any links containing query parameters in the message body to be broken.

Thus in the above case, the body received will be

[Click here](http://www.example.com?param1=value1&param2=value2&param3=value3) 

instead of being

[Click here](http://www.example.com?param1=value1&param2=value2&param3=value3)