How to report iMessage spam

Although I have not been on the receiving end of spam via iMessage (knock on wood), it’s good to know there is a means to report the problem:

…please send an email with the following details to: imessage.spam@icloud.com

Include a screenshot of the message you have received.
Include the full email address or phone number you received the unwanted message from.
Include the date and time that you received the message.