Add Stream::size_hint #1853
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Add Stream::size_hint #1853
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taiki-e commented Sep 1, 2019
| /// A convenience for streams that return `Result` values that includes | ||
| /// a variety of adapters tailored to such futures. | ||
| pub trait TryStream: private_try_stream::Sealed { | ||
| pub trait TryStream: Stream + private_try_stream::Sealed { |
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Added this bound because it would be convenient if stream.size_hint() could be called on St: TryStream.
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oh...
error[E0191]: the value of the associated type `Item` (from the trait `futures_core::stream::Stream`) must be specified --> futures/tests/object_safety.rs:20:30 | 20 | assert_is_object_safe::<&dyn TryStream<Ok = (), Error = ()>>(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ associated type `Item` must be specified taiki-e commented Sep 1, 2019
| /// A convenience for futures that return `Result` values that includes | ||
| /// a variety of adapters tailored to such futures. | ||
| pub trait TryFuture: private_try_future::Sealed { | ||
| pub trait TryFuture: Future + private_try_future::Sealed { |
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Added for consistency with TryStream.
taiki-e force-pushed the stream-size-hint branch from e2ae231 to 3415a86 Compare 
yoshuawuyts approved these changes Sep 1, 2019
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I'm really into this! Similar to Iterator::size_hint and poll_read_vectored this seems like a method that's really useful to significantly help speed up certain code paths!
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| Nice! Seems like a good easy add. |
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Closes #170
r? @cramertj
cc @Nemo157 @seanmonstar @carllerche @LucioFranco @yoshuawuyts