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ChangeEventStream

laminar_core::subscription

Struct ChangeEventStream 

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pub struct ChangeEventStream { /* private fields */ }
Expand description

Async stream wrapper for push subscriptions.

Implements Stream<Item = ChangeEvent>, silently skipping lagged events (with a tracing::debug! log). The stream terminates when the source is closed or the subscription is cancelled.

All fields are Unpin (including BroadcastStream), so the struct is Unpin and works directly with tokio::select! without explicit pinning.

Dropping the stream automatically cancels the subscription in the registry.

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impl ChangeEventStream

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pub fn id(&self) -> SubscriptionId

Returns the subscription ID.

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pub fn query(&self) -> &str

Returns the query or source name for this subscription.

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pub fn is_terminated(&self) -> bool

Returns true if the stream has terminated.

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pub fn pause(&self) -> bool

Pauses the underlying subscription.

While paused, events are buffered or dropped per the backpressure configuration. Returns true if the subscription was active and is now paused.

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pub fn resume(&self) -> bool

Resumes the underlying subscription.

Returns true if the subscription was paused and is now active.

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pub fn cancel(&mut self)

Cancels the subscription and terminates the stream.

Subsequent calls to poll_next / next() return None.

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pub fn metrics(&self) -> Option<SubscriptionMetrics>

Returns subscription metrics from the registry.

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impl Drop for ChangeEventStream

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fn drop(&mut self)

Executes the destructor for this type. Read more
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impl Stream for ChangeEventStream

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type Item = ChangeEvent

Values yielded by the stream.
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fn poll_next( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Option<Self::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted. Read more
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fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream. Read more

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> ArchivePointee for T

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type ArchivedMetadata = ()

The archived version of the pointer metadata for this type.
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fn pointer_metadata( _: &<T as ArchivePointee>::ArchivedMetadata, ) -> <T as Pointee>::Metadata

Converts some archived metadata to the pointer metadata for itself.
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided [Span], returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> LayoutRaw for T

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fn layout_raw(_: <T as Pointee>::Metadata) -> Result<Layout, LayoutError>

Returns the layout of the type.
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impl<T, N1, N2> Niching<NichedOption<T, N1>> for N2
where T: SharedNiching<N1, N2>, N1: Niching<T>, N2: Niching<T>,

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unsafe fn is_niched(niched: *const NichedOption<T, N1>) -> bool

Returns whether the given value has been niched. Read more
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fn resolve_niched(out: Place<NichedOption<T, N1>>)

Writes data to out indicating that a T is niched.
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impl<T> Pointee for T

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type Metadata = ()

The metadata type for pointers and references to this type.
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impl<T> PolicyExt for T
where T: ?Sized,

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fn and<P, B, E>(self, other: P) -> And<T, P>
where T: Policy<B, E>, P: Policy<B, E>,

Create a new Policy that returns [Action::Follow] only if self and other return Action::Follow. Read more
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fn or<P, B, E>(self, other: P) -> Or<T, P>
where T: Policy<B, E>, P: Policy<B, E>,

Create a new Policy that returns [Action::Follow] if either self or other returns Action::Follow. Read more
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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T> Scope for T

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fn with<F, R>(self, f: F) -> R
where Self: Sized, F: FnOnce(Self) -> R,

Scoped with ownership.
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fn with_ref<F, R>(&self, f: F) -> R
where F: FnOnce(&Self) -> R,

Scoped with reference.
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fn with_mut<F, R>(&mut self, f: F) -> R
where F: FnOnce(&mut Self) -> R,

Scoped with mutable reference.
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impl<St> StreamExt for St
where St: Stream + ?Sized,

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fn next(&mut self) -> Next<'_, Self>
where Self: Unpin,

Consumes and returns the next value in the stream or None if the stream is finished. Read more
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fn try_next<T, E>(&mut self) -> TryNext<'_, Self>
where Self: Stream<Item = Result<T, E>> + Unpin,

Consumes and returns the next item in the stream. If an error is encountered before the next item, the error is returned instead. Read more
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fn map<T, F>(self, f: F) -> Map<Self, F>
where F: FnMut(Self::Item) -> T, Self: Sized,

Maps this stream’s items to a different type, returning a new stream of the resulting type. Read more
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fn map_while<T, F>(self, f: F) -> MapWhile<Self, F>
where F: FnMut(Self::Item) -> Option<T>, Self: Sized,

Map this stream’s items to a different type for as long as determined by the provided closure. A stream of the target type will be returned, which will yield elements until the closure returns None. Read more
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fn then<F, Fut>(self, f: F) -> Then<Self, Fut, F>
where F: FnMut(Self::Item) -> Fut, Fut: Future, Self: Sized,

Maps this stream’s items asynchronously to a different type, returning a new stream of the resulting type. Read more
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fn merge<U>(self, other: U) -> Merge<Self, U>
where U: Stream<Item = Self::Item>, Self: Sized,

Combine two streams into one by interleaving the output of both as it is produced. Read more
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fn filter<F>(self, f: F) -> Filter<Self, F>
where F: FnMut(&Self::Item) -> bool, Self: Sized,

Filters the values produced by this stream according to the provided predicate. Read more
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fn filter_map<T, F>(self, f: F) -> FilterMap<Self, F>
where F: FnMut(Self::Item) -> Option<T>, Self: Sized,

Filters the values produced by this stream while simultaneously mapping them to a different type according to the provided closure. Read more
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fn fuse(self) -> Fuse<Self>
where Self: Sized,

Creates a stream which ends after the first None. Read more
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fn take(self, n: usize) -> Take<Self>
where Self: Sized,

Creates a new stream of at most n items of the underlying stream. Read more
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fn take_while<F>(self, f: F) -> TakeWhile<Self, F>
where F: FnMut(&Self::Item) -> bool, Self: Sized,

Take elements from this stream while the provided predicate resolves to true. Read more
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fn skip(self, n: usize) -> Skip<Self>
where Self: Sized,

Creates a new stream that will skip the n first items of the underlying stream. Read more
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fn skip_while<F>(self, f: F) -> SkipWhile<Self, F>
where F: FnMut(&Self::Item) -> bool, Self: Sized,

Skip elements from the underlying stream while the provided predicate resolves to true. Read more
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fn all<F>(&mut self, f: F) -> AllFuture<'_, Self, F>
where Self: Unpin, F: FnMut(Self::Item) -> bool,

Tests if every element of the stream matches a predicate. Read more
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fn any<F>(&mut self, f: F) -> AnyFuture<'_, Self, F>
where Self: Unpin, F: FnMut(Self::Item) -> bool,

Tests if any element of the stream matches a predicate. Read more
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fn chain<U>(self, other: U) -> Chain<Self, U>
where U: Stream<Item = Self::Item>, Self: Sized,

Combine two streams into one by first returning all values from the first stream then all values from the second stream. Read more
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fn fold<B, F>(self, init: B, f: F) -> FoldFuture<Self, B, F>
where Self: Sized, F: FnMut(B, Self::Item) -> B,

A combinator that applies a function to every element in a stream producing a single, final value. Read more
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fn collect<T>( self, ) -> Collect<Self, T, <T as FromStreamPriv<Self::Item>>::InternalCollection>
where T: FromStream<Self::Item>, Self: Sized,

Drain stream pushing all emitted values into a collection. Read more
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fn timeout(self, duration: Duration) -> Timeout<Self>
where Self: Sized,

Applies a per-item timeout to the passed stream. Read more
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fn timeout_repeating(self, interval: Interval) -> TimeoutRepeating<Self>
where Self: Sized,

Applies a per-item timeout to the passed stream. Read more
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fn throttle(self, duration: Duration) -> Throttle<Self>
where Self: Sized,

Slows down a stream by enforcing a delay between items. Read more
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fn chunks_timeout( self, max_size: usize, duration: Duration, ) -> ChunksTimeout<Self>
where Self: Sized,

Batches the items in the given stream using a maximum duration and size for each batch. Read more
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fn peekable(self) -> Peekable<Self>
where Self: Sized,

Turns the stream into a peekable stream, whose next element can be peeked at without being consumed. Read more
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impl<T> StreamExt for T
where T: Stream + ?Sized,

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fn next(&mut self) -> Next<'_, Self>
where Self: Unpin,

Creates a future that resolves to the next item in the stream. Read more
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fn into_future(self) -> StreamFuture<Self>
where Self: Sized + Unpin,

Converts this stream into a future of (next_item, tail_of_stream). If the stream terminates, then the next item is None. Read more
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fn map<T, F>(self, f: F) -> Map<Self, F>
where F: FnMut(Self::Item) -> T, Self: Sized,

Maps this stream’s items to a different type, returning a new stream of the resulting type. Read more
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fn enumerate(self) -> Enumerate<Self>
where Self: Sized,

Creates a stream which gives the current iteration count as well as the next value. Read more
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fn filter<Fut, F>(self, f: F) -> Filter<Self, Fut, F>
where F: FnMut(&Self::Item) -> Fut, Fut: Future<Output = bool>, Self: Sized,

Filters the values produced by this stream according to the provided asynchronous predicate. Read more
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fn filter_map<Fut, T, F>(self, f: F) -> FilterMap<Self, Fut, F>
where F: FnMut(Self::Item) -> Fut, Fut: Future<Output = Option<T>>, Self: Sized,

Filters the values produced by this stream while simultaneously mapping them to a different type according to the provided asynchronous closure. Read more
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fn then<Fut, F>(self, f: F) -> Then<Self, Fut, F>
where F: FnMut(Self::Item) -> Fut, Fut: Future, Self: Sized,

Computes from this stream’s items new items of a different type using an asynchronous closure. Read more
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fn collect<C>(self) -> Collect<Self, C>
where C: Default + Extend<Self::Item>, Self: Sized,

Transforms a stream into a collection, returning a future representing the result of that computation. Read more
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fn unzip<A, B, FromA, FromB>(self) -> Unzip<Self, FromA, FromB>
where FromA: Default + Extend<A>, FromB: Default + Extend<B>, Self: Sized + Stream<Item = (A, B)>,

Converts a stream of pairs into a future, which resolves to pair of containers. Read more
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fn concat(self) -> Concat<Self>
where Self: Sized, Self::Item: Extend<<Self::Item as IntoIterator>::Item> + IntoIterator + Default,

Concatenate all items of a stream into a single extendable destination, returning a future representing the end result. Read more
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fn count(self) -> Count<Self>
where Self: Sized,

Drives the stream to completion, counting the number of items. Read more
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fn cycle(self) -> Cycle<Self>
where Self: Sized + Clone,

Repeats a stream endlessly. Read more
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fn fold<T, Fut, F>(self, init: T, f: F) -> Fold<Self, Fut, T, F>
where F: FnMut(T, Self::Item) -> Fut, Fut: Future<Output = T>, Self: Sized,

Execute an accumulating asynchronous computation over a stream, collecting all the values into one final result. Read more
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fn any<Fut, F>(self, f: F) -> Any<Self, Fut, F>
where F: FnMut(Self::Item) -> Fut, Fut: Future<Output = bool>, Self: Sized,

Execute predicate over asynchronous stream, and return true if any element in stream satisfied a predicate. Read more
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fn all<Fut, F>(self, f: F) -> All<Self, Fut, F>
where F: FnMut(Self::Item) -> Fut, Fut: Future<Output = bool>, Self: Sized,

Execute predicate over asynchronous stream, and return true if all element in stream satisfied a predicate. Read more
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fn flatten(self) -> Flatten<Self>
where Self::Item: Stream, Self: Sized,

Flattens a stream of streams into just one continuous stream. Read more
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fn flatten_unordered( self, limit: impl Into<Option<usize>>, ) -> FlattenUnorderedWithFlowController<Self, ()>
where Self::Item: Stream + Unpin, Self: Sized,

Flattens a stream of streams into just one continuous stream. Polls inner streams produced by the base stream concurrently. Read more
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fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>
where F: FnMut(Self::Item) -> U, U: Stream, Self: Sized,

Maps a stream like [StreamExt::map] but flattens nested Streams. Read more
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fn flat_map_unordered<U, F>( self, limit: impl Into<Option<usize>>, f: F, ) -> FlatMapUnordered<Self, U, F>
where U: Stream + Unpin, F: FnMut(Self::Item) -> U, Self: Sized,

Maps a stream like [StreamExt::map] but flattens nested Streams and polls them concurrently, yielding items in any order, as they made available. Read more
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fn scan<S, B, Fut, F>(self, initial_state: S, f: F) -> Scan<Self, S, Fut, F>
where F: FnMut(&mut S, Self::Item) -> Fut, Fut: Future<Output = Option<B>>, Self: Sized,

Combinator similar to [StreamExt::fold] that holds internal state and produces a new stream. Read more
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fn skip_while<Fut, F>(self, f: F) -> SkipWhile<Self, Fut, F>
where F: FnMut(&Self::Item) -> Fut, Fut: Future<Output = bool>, Self: Sized,

Skip elements on this stream while the provided asynchronous predicate resolves to true. Read more
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fn take_while<Fut, F>(self, f: F) -> TakeWhile<Self, Fut, F>
where F: FnMut(&Self::Item) -> Fut, Fut: Future<Output = bool>, Self: Sized,

Take elements from this stream while the provided asynchronous predicate resolves to true. Read more
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fn take_until<Fut>(self, fut: Fut) -> TakeUntil<Self, Fut>
where Fut: Future, Self: Sized,

Take elements from this stream until the provided future resolves. Read more
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fn for_each<Fut, F>(self, f: F) -> ForEach<Self, Fut, F>
where F: FnMut(Self::Item) -> Fut, Fut: Future<Output = ()>, Self: Sized,

Runs this stream to completion, executing the provided asynchronous closure for each element on the stream. Read more
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fn for_each_concurrent<Fut, F>( self, limit: impl Into<Option<usize>>, f: F, ) -> ForEachConcurrent<Self, Fut, F>
where F: FnMut(Self::Item) -> Fut, Fut: Future<Output = ()>, Self: Sized,

Runs this stream to completion, executing the provided asynchronous closure for each element on the stream concurrently as elements become available. Read more
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fn take(self, n: usize) -> Take<Self>
where Self: Sized,

Creates a new stream of at most n items of the underlying stream. Read more
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fn skip(self, n: usize) -> Skip<Self>
where Self: Sized,

Creates a new stream which skips n items of the underlying stream. Read more
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fn fuse(self) -> Fuse<Self>
where Self: Sized,

Fuse a stream such that poll_next will never again be called once it has finished. This method can be used to turn any Stream into a FusedStream. Read more
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fn by_ref(&mut self) -> &mut Self

Borrows a stream, rather than consuming it. Read more
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fn catch_unwind(self) -> CatchUnwind<Self>
where Self: Sized + UnwindSafe,

Catches unwinding panics while polling the stream. Read more
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fn boxed<'a>(self) -> Pin<Box<dyn Stream<Item = Self::Item> + Send + 'a>>
where Self: Sized + Send + 'a,

Wrap the stream in a Box, pinning it. Read more
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fn boxed_local<'a>(self) -> Pin<Box<dyn Stream<Item = Self::Item> + 'a>>
where Self: Sized + 'a,

Wrap the stream in a Box, pinning it. Read more
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fn buffered(self, n: usize) -> Buffered<Self>
where Self::Item: Future, Self: Sized,

An adaptor for creating a buffered list of pending futures. Read more
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fn buffer_unordered(self, n: usize) -> BufferUnordered<Self>
where Self::Item: Future, Self: Sized,

An adaptor for creating a buffered list of pending futures (unordered). Read more
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fn zip<St>(self, other: St) -> Zip<Self, St>
where St: Stream, Self: Sized,

An adapter for zipping two streams together. Read more
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fn chain<St>(self, other: St) -> Chain<Self, St>
where St: Stream<Item = Self::Item>, Self: Sized,

Adapter for chaining two streams. Read more
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fn peekable(self) -> Peekable<Self>
where Self: Sized,

Creates a new stream which exposes a peek method. Read more
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fn chunks(self, capacity: usize) -> Chunks<Self>
where Self: Sized,

An adaptor for chunking up items of the stream inside a vector. Read more
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fn ready_chunks(self, capacity: usize) -> ReadyChunks<Self>
where Self: Sized,

An adaptor for chunking up ready items of the stream inside a vector. Read more
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fn forward<S>(self, sink: S) -> Forward<Self, S>
where S: Sink<Self::Ok, Error = Self::Error>, Self: Sized + TryStream,

A future that completes after the given stream has been fully processed into the sink and the sink has been flushed and closed. Read more
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fn split<Item>(self) -> (SplitSink<Self, Item>, SplitStream<Self>)
where Self: Sized + Sink<Item>,

Splits this Stream + Sink object into separate Sink and Stream objects. Read more
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fn inspect<F>(self, f: F) -> Inspect<Self, F>
where F: FnMut(&Self::Item), Self: Sized,

Do something with each item of this stream, afterwards passing it on. Read more
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fn left_stream<B>(self) -> Either<Self, B>
where B: Stream<Item = Self::Item>, Self: Sized,

Wrap this stream in an Either stream, making it the left-hand variant of that Either. Read more
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fn right_stream<B>(self) -> Either<B, Self>
where B: Stream<Item = Self::Item>, Self: Sized,

Wrap this stream in an Either stream, making it the right-hand variant of that Either. Read more
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fn poll_next_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Option<Self::Item>>
where Self: Unpin,

A convenience method for calling [Stream::poll_next] on Unpin stream types.
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fn select_next_some(&mut self) -> SelectNextSome<'_, Self>
where Self: Unpin + FusedStream,

Returns a Future that resolves when the next item in this stream is ready. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a [WithDispatch] wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a [WithDispatch] wrapper. Read more
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impl<T> Value for T
where T: Send + Sync + 'static,