Struct EventOptions 

#[non_exhaustive]
pub struct EventOptions {
    pub prepend: bool,
    pub once: bool,
}

on()/on_waterfall() 注册选项(§四偏差清单:prepend 保留,影响 serial/waterfall 结果)。

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

prepend: bool

插到现有监听器之前(默认追加在后)。

once: bool

Claim this registration at most once, when a dispatch selects its snapshot. A preceding short circuit can still skip its actual call.

Implementations

impl EventOptions

pub const fn prepend(self, prepend: bool) -> Self

Insert before the existing listeners instead of after them.

pub const fn once(self, once: bool) -> Self

Claim this registration at most once; see EventOptions::once.

Trait Implementations

impl Clone for EventOptions

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for EventOptions

impl Debug for EventOptions

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

Formats the value using the given formatter.

impl Default for EventOptions

fn default() -> Self

Returns the “default value” for a type.