[ Version ( since = "3.26" ) ]
public void util_set_x_attribute (string x_name, string? value)
Sets an "X-" attribute x_name to value value in this, or removes it from
this, when value is null.
| this |
an VCard |
| x_name |
the attribute name, which starts with "X-" |
| value |
the value to set, or |