Enum Loading 

#[non_exhaustive]
pub enum Loading {
    Eager,
    Lazy,
}

When a picture is needed.

A claim about importance and position rather than a fetch mechanism, which is why it is the description’s to make: only the app knows whether a picture is the first thing on the screen or the fortieth thing down a list.

Eager is the default, and that is a correctness choice

0.21.0 emitted the webview’s loading="lazy" for every picture, on the evidence that the one consumer measured wrote it. That was reading a habit as a rule. Deferring a picture that is on screen at first paint does not save anything – it is needed immediately either way – and it delays the arrival, so the space it eventually takes is claimed later and the shift is more visible, not less.

So the safe answer is the default and the optimisation is opted into. A carousel is the case that proves the two cannot be one setting for the renderer to choose: its first frame is on screen and its other frames are not, in the same widget, at the same moment.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Eager

Needed with the screen. Fetch it now.

Lazy

Not on screen yet. It can wait until it is near.

Trait Implementations

impl Clone for Loading

fn clone(&self) -> Loading

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Loading

impl Debug for Loading

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Loading

fn default() -> Loading

Returns the “default value” for a type.

impl Eq for Loading

impl Hash for Loading

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Loading

fn eq(&self, other: &Loading) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Loading