refactor: replace msgspec.inspect.type_info() with msgspec.structs.…

…fields()`.

As suggested [here](jcrist/msgspec#566 (review)), the `type_info()` function is overkill for this application.

litestar/dto/msgspec_dto.py

@@ -1,17 +1,17 @@
 from __future__ import annotations
 
 from dataclasses import replace
-from typing import TYPE_CHECKING, Collection, Generic, TypeVar, cast
+from typing import TYPE_CHECKING, Generic, TypeVar
 
-from msgspec import NODEFAULT, Struct, inspect
+from msgspec import NODEFAULT, Struct, structs
 
 from litestar.dto.base_dto import AbstractDTO
 from litestar.dto.data_structures import DTOFieldDefinition
 from litestar.dto.field import DTO_FIELD_META_KEY, DTOField
 from litestar.types.empty import Empty
 
 if TYPE_CHECKING:
-    from typing import Any, Generator
+    from typing import Any, Collection, Generator
 
     from litestar.typing import FieldDefinition
 
@@ -26,7 +26,7 @@ class MsgspecDTO(AbstractDTO[T], Generic[T]):
 
     @classmethod
     def generate_field_definitions(cls, model_type: type[Struct]) -> Generator[DTOFieldDefinition, None, None]:
-        msgspec_fields = {f.name: f for f in cast("inspect.StructType", inspect.type_info(model_type)).fields}
+        msgspec_fields = {f.name: f for f in structs.fields(model_type)}
 
         def default_or_empty(value: Any) -> Any:
             return Empty if value is NODEFAULT else value