Struct Mailbox 

pub struct Mailbox<T> { /* private fields */ }

Single-threaded message queue bridging async browser callbacks into the render loop — the standard wasm integration shape every app was inventing (fetch results, WebSocket messages, file reads):

1. Create one Mailbox<Msg> per message stream; clone it into your spawn_local futures and JS callbacks.
2. After start_with_config returns, call Mailbox::set_handle with the WebHandle so pushes wake the host.
3. Mailbox::push from callbacks — it queues the value and requests a redraw.
4. Mailbox::drain in App::before_build and fold the messages into app state; the frame being built sees them.

Clone is a cheap Rc bump (wasm is single-threaded; this type is deliberately not Send). Pushes before set_handle are queued and delivered on the first frame after the host starts.

Implementations

impl<T> Mailbox<T>

pub fn new() -> Self

An empty mailbox with no host attached yet.

pub fn set_handle(&self, handle: WebHandle)

Attach the host’s redraw handle (the WebHandle returned by start_with_config) so subsequent pushes wake the render loop. Idempotent; replaces any previous handle.

pub fn push(&self, value: T)

Queue a message and request a redraw (when a handle is attached). Call from spawn_local futures and JS event callbacks.

pub fn drain(&self) -> Vec<T>

Take every queued message, in push order. Call once per frame from App::before_build.

pub fn is_empty(&self) -> bool

True when nothing is queued.

Trait Implementations

impl<T: Clone> Clone for Mailbox<T>

fn clone(&self) -> Mailbox<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T> Default for Mailbox<T>

fn default() -> Self

Returns the “default value” for a type.