| Value | Meaning |
|---|---|
| UNKNOWN | |
| NOT_LISTENING | The server socket is not listening, but excepted to be. |
| ALREADY_LISTENING | The server socket is already listening, but expected not to be. |
| RESOURCE_FAILED | An operation on the primary underlying resource, e.g. a socket used for accepting connections, failed. |
Error codes for the various types of exceptions.