| # message property | |
| *[<Null safety>](https://dart.dev/null-safety)* | |
| String message | |
| _<span class="feature">final</span>_ | |
| <p>A string indicating the what led to the exception.</p> | |
| <p>This message should be as descriptive as possible since | |
| this exception should not be caught and will lead to a crash.</p> | |
| ## Implementation | |
| ```dart | |
| final String message; | |
| ``` | |