Function lending_iterator::from_stream

pub fn from_stream<S: Stream + Unpin>(stream: S) -> FromStream<S> 

Available on crate feature futures only.

“Lifts” and converts an Unpin Stream into an impl LendingIterator which lends futures (an S, say).

• use {
      ::futures::{
          prelude::*,
      },
      ::lending_iterator::{
          prelude::*,
      },
  };
  
  
  let stream = stream::iter(1..=3);
  let mut lending_iterator = lending_iterator::from_stream(stream);
  loop {
      if let Some(item) = lending_iterator.next().unwrap().await {
          println!("Got `{}`", item);
      } else {
          break;
      }
  }

This could be useful to get access to the more lifetime-powerful adapters of this crate (compared to the adapters on StreamExt, for instance).

• That being said, said adapters often requires the explicitly-turbofished HKT parameter, which in turn requires nameable types.

  Sadly, most impl Future are unnameable!. So you’ll mostly need to use BoxFutures and whatnot.

  For nightly users, however, type_alias_impl_trait can be leveraged to avoid unnecessary Boxing. Keep it in mind!

For instance, here is what a &mut-based “unfold” async iterator construction would look like:

• use {
      ::futures::{
          future::BoxFuture,
          prelude::*,
      },
      ::lending_iterator::{
          prelude::*,
      },
  };
  
  let mut iter =
      lending_iterator::repeat_mut(0)
          .map::<HKT!(BoxFuture<'_, Option<i32>>), _>(
              |[], state: &mut _| async move {
                  if *state <= 2 {
                      let yielded = *state * 2;
                      *state += 1;
                      Some(yielded)
                  } else {
                      None
                  }
              }
              .boxed()
          )
  ;
  let mut result = vec![];
  loop {
      if let Some(item) = iter.next().unwrap().await {
          result.push(item);
      } else {
          break;
      }
  }
  assert_eq!(result, [0, 2, 4]);