change Event to a frozen dataclass (#592)

Author: stevebachmeier

.github/CODEOWNERS

@@ -1,2 +1,2 @@
 # default owners
-* @albrja @collijk @hussain-jafari @patricktnast @rmudambi @stevebachmeier
+* @albrja @hussain-jafari @patricktnast @rmudambi @stevebachmeier

CHANGELOG.rst

@@ -1,5 +1,6 @@
-**3.3.7 - 02/26/25**
+**3.3.7 - 02/27/25**
 
+  - Change Event class to a frozen dataclass
   - Type-hinting: Fix mypy errors in tests/framework/population/test_population_view.py
 
 **3.3.6 - 02/25/25**

src/vivarium/framework/event.py

@@ -29,8 +29,9 @@
 from __future__ import annotations
 
 from collections.abc import Callable
+from dataclasses import dataclass
 from datetime import datetime, timedelta
-from typing import TYPE_CHECKING, Any, NamedTuple
+from typing import TYPE_CHECKING, Any
 
 import pandas as pd
 
@@ -42,16 +43,16 @@
     from vivarium.framework.engine import Builder
 
 
-class Event(NamedTuple):
+@dataclass(frozen=True)
+class Event:
     """An Event object represents the context of an event.
 
     Events themselves are just a bundle of data.  They must be emitted
     along an :class:`EventChannel` in order for other simulation components
     to respond to them.
     """
 
-    # FIXME [MIC-5468]: fix index type hint for mypy
-    index: pd.Index[int]  # type: ignore[assignment]
+    index: pd.Index[int]
     """An index into the population table containing all simulants affected by this event."""
     user_data: dict[str, Any]
     """Any additional data provided by the user about the event."""