# Objective
Implements #9216
## Solution
- Replace `DiagnosticId` by `DiagnosticPath`. It's pre-hashed using
`const-fnv1a-hash` crate, so it's possible to create path in const
contexts.
---
## Changelog
- Replaced `DiagnosticId` by `DiagnosticPath`
- Set default history length to 120 measurements (2 seconds on 60 fps).
I've noticed hardcoded constant 20 everywhere and decided to change it
to `DEFAULT_MAX_HISTORY_LENGTH` , which is set to new diagnostics by
default. To override it, use `with_max_history_length`.
## Migration Guide
```diff
- const UNIQUE_DIAG_ID: DiagnosticId = DiagnosticId::from_u128(42);
+ const UNIQUE_DIAG_PATH: DiagnosticPath = DiagnosticPath::const_new("foo/bar");
- Diagnostic::new(UNIQUE_DIAG_ID, "example", 10)
+ Diagnostic::new(UNIQUE_DIAG_PATH).with_max_history_length(10)
- diagnostics.add_measurement(UNIQUE_DIAG_ID, || 42);
+ diagnostics.add_measurement(&UNIQUE_DIAG_ID, || 42);
```