set_user_header

Description:

[ Version ( since = "3.42" ) ]
public virtual bool set_user_header (string name, string? value)

Set value for a single user-defined message header of the associated message.

When the value is null, the header name is removed from the user-defined headers.

If the this changed, the 'dirty' flag is set automatically, unless the this is aborting notifications. There is not emitted folder's "changed" signal for this this.

Parameters:

this	a MessageInfo
name	header name
value	header value, or null

Returns:

Whether the value changed.