ToSchema doesn't work on one particular #[serde(flatten)]

[cryscan]

Here is the definition of types:

#[derive(Debug, Clone, Derivative, Serialize, Deserialize, ToSchema)]
#[derivative(Default)]
#[serde(default)]
pub struct NucleusParams {
    #[derivative(Default(value = "0.5"))]
    pub top_p: f32,
    #[derivative(Default(value = "128"))]
    pub top_k: usize,
    #[derivative(Default(value = "1.0"))]
    pub temperature: f32,
    #[derivative(Default(value = "0.3"))]
    pub presence_penalty: f32,
    #[derivative(Default(value = "0.3"))]
    pub frequency_penalty: f32,
    #[derivative(Default(value = "0.99654026"))]
    pub penalty_decay: f32,
}



#[derive(Debug, Derivative, Deserialize, ToSchema)]
#[derivative(Default)]
#[serde(default)]
#[salvo(schema(
    example = json!({
        "messages": [
            {
                "role": "user",
                "content": "Hi!"
            },
            {
                "role": "assistant",
                "content": "Hello, I am your AI assistant. If you have any questions or instructions, please let me know!"
            },
            {
                "role": "user",
                "content": "Tell me about water."
            }
        ],
        "names": {
            "user": "User",
            "assistant": "Assistant"
        },
        "template": {
            "record": "{role}: {content}",
            "prefix": "{assistant}:",
            "sep": "\n\n"
        },
        "stop": [
            "\n\nUser:"
        ],
        "stream": false,
        "max_tokens": 1000,
        "sampler_override": {
            "type": "Nucleus",
            "top_p": 0.5,
            "top_k": 128,
            "temperature": 1,
            "presence_penalty": 0.3,
            "frequency_penalty": 0.3,
            "penalty_decay": 0.99654026
        },
        "state": "00000000-0000-0000-0000-000000000000"
    })
))]
struct ChatRequest {
    messages: Array<ChatRecord>,
    names: HashMap<Role, String>,
    template: ChatTemplate,
    state: InputState,
    #[derivative(Default(value = "256"))]
    max_tokens: usize,
    #[derivative(Default(value = "Array::Item(\"\\n\\n\".into())"))]
    stop: Array<String>,
    stream: bool,
    #[serde(alias = "logit_bias")]
    bias: HashMap<u16, f32>,
    bnf_schema: Option<String>,
    #[serde(flatten)]
    sampler: NucleusParams,
    sampler_override: Option<SamplerParams>,
}

With #[serde(flatten)], there is an error on ToSchema:

error[E0599]: no method named `example` found for struct `salvo::salvo_oapi::schema::AllOf` in the current scope
  --> crates\ai00-server\src\api\oai\chat.rs:67:42
   |
67 | #[derive(Debug, Derivative, Deserialize, ToSchema)]
   |                                          ^^^^^^^^
   |
   = note: this error originates in the derive macro `ToSchema` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0599]: no method named `example` found for struct `salvo::salvo_oapi::schema::AllOf` in the current scope
  --> crates\ai00-server\src\api\oai\completion.rs:23:42
   |
23 | #[derive(Debug, Derivative, Deserialize, ToSchema)]
   |                                          ^^^^^^^^
   |
   = note: this error originates in the derive macro `ToSchema` (in Nightly builds, run with -Z macro-backtrace for more info)