Gio.DBusMessage.prototype.set_header

function set_header(header_field: Gio.DBusMessageHeaderField, value: GLib.Variant): void {
    // Gjs wrapper for g_dbus_message_set_header()
}

Sets a header field on message.

If value is floating, message assumes ownership of value.

Since 2.26

header_field: A 8-bit unsigned integer (typically a value from the Gio.DBusMessageHeaderField enumeration)
value: A GLib.Variant to set the header field or null to clear the header field.