Helper function for constructing Initable object.
This is similar to @new but also initializes the object and returns null, setting an error on failure.
| object_type | |
| cancellable |
optional Cancellable object, null to ignore. |
| ... |
the value if the first property, followed by and other property value pairs, and ended by null. |
| error |
a Error location to store the error occurring, or null to ignore. |
| first_property_name |
the name of the first property, or null if no properties |
|
a newly allocated Object, or null on error |