pub struct Cloned<S> { /* private fields */ }
Expand description
A stream that clones the elements of an underlying stream.
Trait Implementations
sourceimpl<'a, S, T: 'a> Stream for Cloned<S> where
S: Stream<Item = &'a T>,
T: Clone,
impl<'a, S, T: 'a> Stream for Cloned<S> where
S: Stream<Item = &'a T>,
T: Clone,
type Item = T
type Item = T
Values yielded by the stream.
impl<'__pin, S> Unpin for Cloned<S> where
__Origin<'__pin, S>: Unpin,
Auto Trait Implementations
impl<S> RefUnwindSafe for Cloned<S> where
S: RefUnwindSafe,
impl<S> Send for Cloned<S> where
S: Send,
impl<S> Sync for Cloned<S> where
S: Sync,
impl<S> UnwindSafe for Cloned<S> where
S: UnwindSafe,
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<S> StreamExt for S where
S: Stream + ?Sized,
impl<S> StreamExt for S where
S: Stream + ?Sized,
sourcefn poll_next(&mut self, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> where
Self: Unpin,
fn poll_next(&mut self, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> where
Self: Unpin,
A convenience for calling Stream::poll_next()
on !
Unpin
types.
sourcefn next(&mut self) -> NextFuture<'_, Self>ⓘNotable traits for NextFuture<'_, S>impl<'_, S> Future for NextFuture<'_, S> where
S: Stream + Unpin + ?Sized, type Output = Option<<S as Stream>::Item>;
where
Self: Unpin,
fn next(&mut self) -> NextFuture<'_, Self>ⓘNotable traits for NextFuture<'_, S>impl<'_, S> Future for NextFuture<'_, S> where
S: Stream + Unpin + ?Sized, type Output = Option<<S as Stream>::Item>;
where
Self: Unpin,
S: Stream + Unpin + ?Sized, type Output = Option<<S as Stream>::Item>;
Retrieves the next item in the stream. Read more
sourcefn try_next<T, E>(&mut self) -> TryNextFuture<'_, Self>ⓘNotable traits for TryNextFuture<'_, S>impl<'_, T, E, S> Future for TryNextFuture<'_, S> where
S: Stream<Item = Result<T, E>> + Unpin + ?Sized, type Output = Result<Option<T>, E>;
where
Self: Stream<Item = Result<T, E>> + Unpin,
fn try_next<T, E>(&mut self) -> TryNextFuture<'_, Self>ⓘNotable traits for TryNextFuture<'_, S>impl<'_, T, E, S> Future for TryNextFuture<'_, S> where
S: Stream<Item = Result<T, E>> + Unpin + ?Sized, type Output = Result<Option<T>, E>;
where
Self: Stream<Item = Result<T, E>> + Unpin,
S: Stream<Item = Result<T, E>> + Unpin + ?Sized, type Output = Result<Option<T>, E>;
Retrieves the next item in the stream. Read more
sourcefn count(self) -> CountFuture<Self>ⓘNotable traits for CountFuture<S>impl<S> Future for CountFuture<S> where
S: Stream + ?Sized, type Output = usize;
fn count(self) -> CountFuture<Self>ⓘNotable traits for CountFuture<S>impl<S> Future for CountFuture<S> where
S: Stream + ?Sized, type Output = usize;
S: Stream + ?Sized, type Output = usize;
Counts the number of items in the stream. Read more
sourcefn map<T, F>(self, f: F) -> Map<Self, F> where
F: FnMut(Self::Item) -> T,
fn map<T, F>(self, f: F) -> Map<Self, F> where
F: FnMut(Self::Item) -> T,
Maps items of the stream to new values using a closure. Read more
sourcefn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where
U: Stream,
F: FnMut(Self::Item) -> U,
fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where
U: Stream,
F: FnMut(Self::Item) -> U,
Maps items to streams and then concatenates them. Read more
sourcefn flatten(self) -> Flatten<Self> where
Self::Item: Stream,
fn flatten(self) -> Flatten<Self> where
Self::Item: Stream,
Concatenates inner streams. Read more
sourcefn then<F, Fut>(self, f: F) -> Then<Self, F, Fut> where
F: FnMut(Self::Item) -> Fut,
Fut: Future,
fn then<F, Fut>(self, f: F) -> Then<Self, F, Fut> where
F: FnMut(Self::Item) -> Fut,
Fut: Future,
Maps items of the stream to new values using an async closure. Read more
sourcefn filter<P>(self, predicate: P) -> Filter<Self, P> where
P: FnMut(&Self::Item) -> bool,
fn filter<P>(self, predicate: P) -> Filter<Self, P> where
P: FnMut(&Self::Item) -> bool,
Keeps items of the stream for which predicate
returns true
. Read more
sourcefn filter_map<T, F>(self, f: F) -> FilterMap<Self, F> where
F: FnMut(Self::Item) -> Option<T>,
fn filter_map<T, F>(self, f: F) -> FilterMap<Self, F> where
F: FnMut(Self::Item) -> Option<T>,
Filters and maps items of the stream using a closure. Read more
sourcefn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where
P: FnMut(&Self::Item) -> bool,
fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where
P: FnMut(&Self::Item) -> bool,
Takes items while predicate
returns true
. Read more
sourcefn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where
P: FnMut(&Self::Item) -> bool,
fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where
P: FnMut(&Self::Item) -> bool,
Skips items while predicate
returns true
. Read more
sourcefn chain<U>(self, other: U) -> Chain<Self, U> where
U: Stream<Item = Self::Item>,
fn chain<U>(self, other: U) -> Chain<Self, U> where
U: Stream<Item = Self::Item>,
Appends another stream to the end of this one. Read more
sourcefn cloned<'a, T>(self) -> Cloned<Self> where
Self: Stream<Item = &'a T>,
T: 'a + Clone,
fn cloned<'a, T>(self) -> Cloned<Self> where
Self: Stream<Item = &'a T>,
T: 'a + Clone,
Clones all items. Read more
sourcefn copied<'a, T>(self) -> Copied<Self> where
Self: Stream<Item = &'a T>,
T: 'a + Copy,
fn copied<'a, T>(self) -> Copied<Self> where
Self: Stream<Item = &'a T>,
T: 'a + Copy,
Copies all items. Read more
sourcefn collect<C>(self) -> CollectFuture<Self, C>ⓘNotable traits for CollectFuture<S, C>impl<S, C> Future for CollectFuture<S, C> where
S: Stream,
C: Default + Extend<<S as Stream>::Item>, type Output = C;
where
C: Default + Extend<Self::Item>,
fn collect<C>(self) -> CollectFuture<Self, C>ⓘNotable traits for CollectFuture<S, C>impl<S, C> Future for CollectFuture<S, C> where
S: Stream,
C: Default + Extend<<S as Stream>::Item>, type Output = C;
where
C: Default + Extend<Self::Item>,
S: Stream,
C: Default + Extend<<S as Stream>::Item>, type Output = C;
Collects all items in the stream into a collection. Read more
sourcefn try_collect<T, E, C>(self) -> TryCollectFuture<Self, C>ⓘNotable traits for TryCollectFuture<S, C>impl<T, E, S, C> Future for TryCollectFuture<S, C> where
S: Stream<Item = Result<T, E>>,
C: Default + Extend<T>, type Output = Result<C, E>;
where
Self: Stream<Item = Result<T, E>>,
C: Default + Extend<T>,
fn try_collect<T, E, C>(self) -> TryCollectFuture<Self, C>ⓘNotable traits for TryCollectFuture<S, C>impl<T, E, S, C> Future for TryCollectFuture<S, C> where
S: Stream<Item = Result<T, E>>,
C: Default + Extend<T>, type Output = Result<C, E>;
where
Self: Stream<Item = Result<T, E>>,
C: Default + Extend<T>,
S: Stream<Item = Result<T, E>>,
C: Default + Extend<T>, type Output = Result<C, E>;
Collects all items in the fallible stream into a collection. Read more
sourcefn partition<B, P>(self, predicate: P) -> PartitionFuture<Self, P, B>ⓘNotable traits for PartitionFuture<S, P, B>impl<S, P, B> Future for PartitionFuture<S, P, B> where
S: Stream,
P: FnMut(&<S as Stream>::Item) -> bool,
B: Default + Extend<<S as Stream>::Item>, type Output = (B, B);
where
B: Default + Extend<Self::Item>,
P: FnMut(&Self::Item) -> bool,
fn partition<B, P>(self, predicate: P) -> PartitionFuture<Self, P, B>ⓘNotable traits for PartitionFuture<S, P, B>impl<S, P, B> Future for PartitionFuture<S, P, B> where
S: Stream,
P: FnMut(&<S as Stream>::Item) -> bool,
B: Default + Extend<<S as Stream>::Item>, type Output = (B, B);
where
B: Default + Extend<Self::Item>,
P: FnMut(&Self::Item) -> bool,
S: Stream,
P: FnMut(&<S as Stream>::Item) -> bool,
B: Default + Extend<<S as Stream>::Item>, type Output = (B, B);
Partitions items into those for which predicate
is true
and those for which it is
false
, and then collects them into two collections. Read more
sourcefn fold<T, F>(self, init: T, f: F) -> FoldFuture<Self, F, T>ⓘNotable traits for FoldFuture<S, F, T>impl<S, F, T> Future for FoldFuture<S, F, T> where
S: Stream,
F: FnMut(T, <S as Stream>::Item) -> T, type Output = T;
where
F: FnMut(T, Self::Item) -> T,
fn fold<T, F>(self, init: T, f: F) -> FoldFuture<Self, F, T>ⓘNotable traits for FoldFuture<S, F, T>impl<S, F, T> Future for FoldFuture<S, F, T> where
S: Stream,
F: FnMut(T, <S as Stream>::Item) -> T, type Output = T;
where
F: FnMut(T, Self::Item) -> T,
S: Stream,
F: FnMut(T, <S as Stream>::Item) -> T, type Output = T;
Accumulates a computation over the stream. Read more
sourcefn try_fold<T, E, F, B>(
&mut self,
init: B,
f: F
) -> TryFoldFuture<'_, Self, F, B>ⓘNotable traits for TryFoldFuture<'a, S, F, B>impl<'a, T, E, S, F, B> Future for TryFoldFuture<'a, S, F, B> where
S: Stream<Item = Result<T, E>> + Unpin,
F: FnMut(B, T) -> Result<B, E>, type Output = Result<B, E>;
where
Self: Stream<Item = Result<T, E>> + Unpin,
F: FnMut(B, T) -> Result<B, E>,
fn try_fold<T, E, F, B>(
&mut self,
init: B,
f: F
) -> TryFoldFuture<'_, Self, F, B>ⓘNotable traits for TryFoldFuture<'a, S, F, B>impl<'a, T, E, S, F, B> Future for TryFoldFuture<'a, S, F, B> where
S: Stream<Item = Result<T, E>> + Unpin,
F: FnMut(B, T) -> Result<B, E>, type Output = Result<B, E>;
where
Self: Stream<Item = Result<T, E>> + Unpin,
F: FnMut(B, T) -> Result<B, E>,
S: Stream<Item = Result<T, E>> + Unpin,
F: FnMut(B, T) -> Result<B, E>, type Output = Result<B, E>;
Accumulates a fallible computation over the stream. Read more
sourcefn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where
F: FnMut(&mut St, Self::Item) -> Option<B>,
fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where
F: FnMut(&mut St, Self::Item) -> Option<B>,
Maps items of the stream to new values using a state value and a closure. Read more
sourcefn cycle(self) -> Cycle<Self> where
Self: Clone,
fn cycle(self) -> Cycle<Self> where
Self: Clone,
Repeats the stream from beginning to end, forever. Read more
sourcefn enumerate(self) -> Enumerate<Self>
fn enumerate(self) -> Enumerate<Self>
Enumerates items, mapping them to (index, item)
. Read more
sourcefn inspect<F>(self, f: F) -> Inspect<Self, F> where
F: FnMut(&Self::Item),
fn inspect<F>(self, f: F) -> Inspect<Self, F> where
F: FnMut(&Self::Item),
Calls a closure on each item and passes it on. Read more
sourcefn nth(&mut self, n: usize) -> NthFuture<'_, Self>ⓘNotable traits for NthFuture<'a, S>impl<'a, S> Future for NthFuture<'a, S> where
S: Stream + Unpin + ?Sized, type Output = Option<<S as Stream>::Item>;
where
Self: Unpin,
fn nth(&mut self, n: usize) -> NthFuture<'_, Self>ⓘNotable traits for NthFuture<'a, S>impl<'a, S> Future for NthFuture<'a, S> where
S: Stream + Unpin + ?Sized, type Output = Option<<S as Stream>::Item>;
where
Self: Unpin,
S: Stream + Unpin + ?Sized, type Output = Option<<S as Stream>::Item>;
Gets the n
th item of the stream. Read more
sourcefn last(self) -> LastFuture<Self>ⓘNotable traits for LastFuture<S>impl<S> Future for LastFuture<S> where
S: Stream, type Output = Option<<S as Stream>::Item>;
fn last(self) -> LastFuture<Self>ⓘNotable traits for LastFuture<S>impl<S> Future for LastFuture<S> where
S: Stream, type Output = Option<<S as Stream>::Item>;
S: Stream, type Output = Option<<S as Stream>::Item>;
Returns the last item in the stream. Read more
sourcefn find<P>(&mut self, predicate: P) -> FindFuture<'_, Self, P>ⓘNotable traits for FindFuture<'a, S, P>impl<'a, S, P> Future for FindFuture<'a, S, P> where
S: Stream + Unpin + ?Sized,
P: FnMut(&<S as Stream>::Item) -> bool, type Output = Option<<S as Stream>::Item>;
where
Self: Unpin,
P: FnMut(&Self::Item) -> bool,
fn find<P>(&mut self, predicate: P) -> FindFuture<'_, Self, P>ⓘNotable traits for FindFuture<'a, S, P>impl<'a, S, P> Future for FindFuture<'a, S, P> where
S: Stream + Unpin + ?Sized,
P: FnMut(&<S as Stream>::Item) -> bool, type Output = Option<<S as Stream>::Item>;
where
Self: Unpin,
P: FnMut(&Self::Item) -> bool,
S: Stream + Unpin + ?Sized,
P: FnMut(&<S as Stream>::Item) -> bool, type Output = Option<<S as Stream>::Item>;
Finds the first item of the stream for which predicate
returns true
. Read more
sourcefn find_map<F, B>(&mut self, f: F) -> FindMapFuture<'_, Self, F>ⓘNotable traits for FindMapFuture<'a, S, F>impl<'a, S, B, F> Future for FindMapFuture<'a, S, F> where
S: Stream + Unpin + ?Sized,
F: FnMut(<S as Stream>::Item) -> Option<B>, type Output = Option<B>;
where
Self: Unpin,
F: FnMut(Self::Item) -> Option<B>,
fn find_map<F, B>(&mut self, f: F) -> FindMapFuture<'_, Self, F>ⓘNotable traits for FindMapFuture<'a, S, F>impl<'a, S, B, F> Future for FindMapFuture<'a, S, F> where
S: Stream + Unpin + ?Sized,
F: FnMut(<S as Stream>::Item) -> Option<B>, type Output = Option<B>;
where
Self: Unpin,
F: FnMut(Self::Item) -> Option<B>,
S: Stream + Unpin + ?Sized,
F: FnMut(<S as Stream>::Item) -> Option<B>, type Output = Option<B>;
sourcefn position<P>(&mut self, predicate: P) -> PositionFuture<'_, Self, P>ⓘNotable traits for PositionFuture<'a, S, P>impl<'a, S, P> Future for PositionFuture<'a, S, P> where
S: Stream + Unpin + ?Sized,
P: FnMut(<S as Stream>::Item) -> bool, type Output = Option<usize>;
where
Self: Unpin,
P: FnMut(Self::Item) -> bool,
fn position<P>(&mut self, predicate: P) -> PositionFuture<'_, Self, P>ⓘNotable traits for PositionFuture<'a, S, P>impl<'a, S, P> Future for PositionFuture<'a, S, P> where
S: Stream + Unpin + ?Sized,
P: FnMut(<S as Stream>::Item) -> bool, type Output = Option<usize>;
where
Self: Unpin,
P: FnMut(Self::Item) -> bool,
S: Stream + Unpin + ?Sized,
P: FnMut(<S as Stream>::Item) -> bool, type Output = Option<usize>;
Finds the index of the first item of the stream for which predicate
returns true
. Read more
sourcefn all<P>(&mut self, predicate: P) -> AllFuture<'_, Self, P>ⓘNotable traits for AllFuture<'_, S, P>impl<'_, S, P> Future for AllFuture<'_, S, P> where
S: Stream + Unpin + ?Sized,
P: FnMut(<S as Stream>::Item) -> bool, type Output = bool;
where
Self: Unpin,
P: FnMut(Self::Item) -> bool,
fn all<P>(&mut self, predicate: P) -> AllFuture<'_, Self, P>ⓘNotable traits for AllFuture<'_, S, P>impl<'_, S, P> Future for AllFuture<'_, S, P> where
S: Stream + Unpin + ?Sized,
P: FnMut(<S as Stream>::Item) -> bool, type Output = bool;
where
Self: Unpin,
P: FnMut(Self::Item) -> bool,
S: Stream + Unpin + ?Sized,
P: FnMut(<S as Stream>::Item) -> bool, type Output = bool;
Tests if predicate
returns true
for all items in the stream. Read more
sourcefn any<P>(&mut self, predicate: P) -> AnyFuture<'_, Self, P>ⓘNotable traits for AnyFuture<'_, S, P>impl<'_, S, P> Future for AnyFuture<'_, S, P> where
S: Stream + Unpin + ?Sized,
P: FnMut(<S as Stream>::Item) -> bool, type Output = bool;
where
Self: Unpin,
P: FnMut(Self::Item) -> bool,
fn any<P>(&mut self, predicate: P) -> AnyFuture<'_, Self, P>ⓘNotable traits for AnyFuture<'_, S, P>impl<'_, S, P> Future for AnyFuture<'_, S, P> where
S: Stream + Unpin + ?Sized,
P: FnMut(<S as Stream>::Item) -> bool, type Output = bool;
where
Self: Unpin,
P: FnMut(Self::Item) -> bool,
S: Stream + Unpin + ?Sized,
P: FnMut(<S as Stream>::Item) -> bool, type Output = bool;
Tests if predicate
returns true
for any item in the stream. Read more
sourcefn for_each<F>(self, f: F) -> ForEachFuture<Self, F>ⓘNotable traits for ForEachFuture<S, F>impl<S, F> Future for ForEachFuture<S, F> where
S: Stream,
F: FnMut(<S as Stream>::Item), type Output = ();
where
F: FnMut(Self::Item),
fn for_each<F>(self, f: F) -> ForEachFuture<Self, F>ⓘNotable traits for ForEachFuture<S, F>impl<S, F> Future for ForEachFuture<S, F> where
S: Stream,
F: FnMut(<S as Stream>::Item), type Output = ();
where
F: FnMut(Self::Item),
S: Stream,
F: FnMut(<S as Stream>::Item), type Output = ();
Calls a closure on each item of the stream. Read more
sourcefn try_for_each<F, E>(&mut self, f: F) -> TryForEachFuture<'_, Self, F>ⓘNotable traits for TryForEachFuture<'a, S, F>impl<'a, S, F, E> Future for TryForEachFuture<'a, S, F> where
S: Stream + Unpin + ?Sized,
F: FnMut(<S as Stream>::Item) -> Result<(), E>, type Output = Result<(), E>;
where
Self: Unpin,
F: FnMut(Self::Item) -> Result<(), E>,
fn try_for_each<F, E>(&mut self, f: F) -> TryForEachFuture<'_, Self, F>ⓘNotable traits for TryForEachFuture<'a, S, F>impl<'a, S, F, E> Future for TryForEachFuture<'a, S, F> where
S: Stream + Unpin + ?Sized,
F: FnMut(<S as Stream>::Item) -> Result<(), E>, type Output = Result<(), E>;
where
Self: Unpin,
F: FnMut(Self::Item) -> Result<(), E>,
S: Stream + Unpin + ?Sized,
F: FnMut(<S as Stream>::Item) -> Result<(), E>, type Output = Result<(), E>;
Calls a fallible closure on each item of the stream, stopping on first error. Read more
sourcefn zip<U>(self, other: U) -> Zip<Self, U> where
U: Stream,
fn zip<U>(self, other: U) -> Zip<Self, U> where
U: Stream,
Zips up two streams into a single stream of pairs. Read more
sourcefn unzip<A, B, FromA, FromB>(self) -> UnzipFuture<Self, FromA, FromB>ⓘNotable traits for UnzipFuture<S, FromA, FromB>impl<S, A, B, FromA, FromB> Future for UnzipFuture<S, FromA, FromB> where
S: Stream<Item = (A, B)>,
FromA: Default + Extend<A>,
FromB: Default + Extend<B>, type Output = (FromA, FromB);
where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Stream<Item = (A, B)>,
fn unzip<A, B, FromA, FromB>(self) -> UnzipFuture<Self, FromA, FromB>ⓘNotable traits for UnzipFuture<S, FromA, FromB>impl<S, A, B, FromA, FromB> Future for UnzipFuture<S, FromA, FromB> where
S: Stream<Item = (A, B)>,
FromA: Default + Extend<A>,
FromB: Default + Extend<B>, type Output = (FromA, FromB);
where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Stream<Item = (A, B)>,
S: Stream<Item = (A, B)>,
FromA: Default + Extend<A>,
FromB: Default + Extend<B>, type Output = (FromA, FromB);
Collects a stream of pairs into a pair of collections. Read more
sourcefn or<S>(self, other: S) -> Or<Self, S> where
S: Stream<Item = Self::Item>,
fn or<S>(self, other: S) -> Or<Self, S> where
S: Stream<Item = Self::Item>,
Merges with other
stream, preferring items from self
whenever both streams are ready. Read more
sourcefn race<S>(self, other: S) -> Race<Self, S> where
S: Stream<Item = Self::Item>,
fn race<S>(self, other: S) -> Race<Self, S> where
S: Stream<Item = Self::Item>,
Merges with other
stream, with no preference for either stream when both are ready. Read more
sourcefn boxed<'a>(
self
) -> Pin<Box<dyn Stream<Item = Self::Item> + Send + 'a, Global>>ⓘNotable traits for Pin<P>impl<P> Future for Pin<P> where
P: DerefMut,
<P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
where
Self: 'a + Send,
fn boxed<'a>(
self
) -> Pin<Box<dyn Stream<Item = Self::Item> + Send + 'a, Global>>ⓘNotable traits for Pin<P>impl<P> Future for Pin<P> where
P: DerefMut,
<P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
where
Self: 'a + Send,
P: DerefMut,
<P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
Boxes the stream and changes its type to dyn Stream + Send + 'a
. Read more
sourcefn boxed_local<'a>(self) -> Pin<Box<dyn Stream<Item = Self::Item> + 'a, Global>>ⓘNotable traits for Pin<P>impl<P> Future for Pin<P> where
P: DerefMut,
<P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
where
Self: 'a,
fn boxed_local<'a>(self) -> Pin<Box<dyn Stream<Item = Self::Item> + 'a, Global>>ⓘNotable traits for Pin<P>impl<P> Future for Pin<P> where
P: DerefMut,
<P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
where
Self: 'a,
P: DerefMut,
<P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
Boxes the stream and changes its type to dyn Stream + 'a
. Read more