add-mime-header
Returns a stream with added header key: value. This function does not remove an existing header with that key.
Signature
add-mime-header(s:stream, key:string, value:string) -> stream  | 
Parameters
Name  | Type  | Description  | 
|---|---|---|
s  | stream  | The stream to which the header should be added.  | 
key  | string  | The key from the key-value pair.  | 
value  | string  | The value from the key-value pair.  |