A proxy identity added to the space.
| Property | Description |
|---|---|
| Id | The Id of the proxy. |
| isValid | Whether this handle refers to a valid proxy slot. A default-constructed handle is always invalid. This does not check that the proxy still exists in any specific space, that the underlying tree slot has not been reused, or that this handle belongs to the space it is passed to. Those are checked when the handle is used. |