Workers - MessageChannel and MessagePort
A minimal implementation of the MessageChannel API is now available in Workers. This means that you can use MessageChannel to send messages between different parts of your Worker, but not across different Workers. The MessageChannel and MessagePort APIs will be available by default at the global scope with any worker using a compatibility date of 2025-08-15 or later. It is also available using the expose_global_message_channel compatibility flag, or can be explicitly disabled using the no_expose
