A Registrar keeps a map of lookup string to anything. Generally, this is used to keep a directory of long-lived service-providing actors that can be looked up name.
- Registrar tag^
Add, or change, a lookup mapping.
Remove a mapping. This only takes effect if provided key currently maps to the provided value. If the key maps to some other value (perhaps after updating), the mapping won't be removed.
Lookup by name. Returns a promise that will be fulfilled with the mapped value if it exists and is a subtype of A. Otherwise, the promise will be rejected.
- key: String val
- Promise[A] tag