Returns a stream with the "Content-ID" header set to value, and all other headers and content untouched. You can also achieve the same result using the set-mime-header function; this function represents a more direct approach.
set-mime-content-id(s:stream, value:string="") -> stream  | 
Name  | 
Type  | 
Description  | 
|---|---|---|
s  | 
stream  | 
Specifies the input string.  | 
value  | 
string  | 
Specifies the value to set in the "Content-Disposition".  | 
Let's assume that you want to set the value of the "Content-ID" header in stream msg to <root.attachment>. To do this, use the following expression:
set-mime-content-id(msg, "<root.attachment>")  |