Trait HasLoadingHint 

pub trait HasLoadingHint: Clone + 'static {
    // Required method
    fn empty() -> Self;
}

Optional payload for the Loading state.

Most users will leave this at the default () — the variant then carries no information beyond “we’re fetching”. Implement this trait for your loading-hint type to attach stale-while- revalidate metadata (last-known data, fetched-at timestamp, …) to the Loading arm.

The trait has a single associated constant — a zero-sized marker so the type can be used as a default type parameter — and one method that produces the “no prior data, no hint” sentinel.

Examples

#[derive(Clone)]
struct Hint { previous: Option<MyData>, last_fetched_ms: u64 }

impl HasLoadingHint for Hint {
    fn empty() -> Self { Hint { previous: None, last_fetched_ms: 0 } }
}

Required Methods

fn empty() -> Self

The sentinel value representing “no prior data is available”. use_async slots this in for the first render so that .loading_hint() always returns a usable value, even before the future has a chance to produce one.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl HasLoadingHint for ()

fn empty() -> Self

Implementors