Missing `#/components/schemas/LevelOne` when creating `msgspec.Struct`-based class whose attributes are also `msgspec.Struct`-based class

[vhbui02]

In short, nested msgspec.Struct simply doesn't work:

# .env.example
QUART_SCHEMA_CONVERSION_PREFERENCE=msgspec

# test.py
class LevelOne(msgspec.Struct):
  a: int
  b: str

class LevelTwo(msgspec.Struct):
  lvl_one: LevelOne

#/components/schemas/LevelOne can't be found in /openapi.json

I've identified the code which leads to this behavior:

# quart_schema/conversion.py
# ...
def model_schema(
    model_class: type[Model],
    *,
    preference: str | None = None,
    schema_mode: JsonSchemaMode = "validation",
) -> dict:
    if _use_pydantic(model_class, preference):
        return TypeAdapter(model_class).json_schema(
            ref_template=PYDANTIC_REF_TEMPLATE, mode=schema_mode
        )
    elif _use_msgspec(model_class, preference):
        _, schema = schema_components([model_class], ref_template=MSGSPEC_REF_TEMPLATE)
        return list(schema.values())[0]
    elif not PYDANTIC_INSTALLED and not MSGSPEC_INSTALLED:
        raise TypeError(
            f"Cannot create schema for {model_class} - try installing msgspec or pydantic"
        )
    else:
        raise TypeError(f"Cannot create schema for {model_class}")
# ...

I see that you omit the definitions when msgspec is used. I've tried to add it but no LevelOne is found (not to mention sometimes circular dependency occurs). Is this behavior the way it is? I can workaround with Pydantic but I loved the performance gain by msgspec.