Merge remote-tracking branch 'origin/upstream' am: 93e24a1529 am: 3c3c2a56ab

Original change: undetermined

Change-Id: I96ea8b8846bfad4cb15a1906407f7a5fcae6da48
Signed-off-by: Automerger Merge Worker <[email protected]>
tree: 0ebf1cbe148a67ad9b109b9a07851d6ebd5dff24
  1. benches/
  2. src/
  3. Android.bp
  4. Cargo.toml
  5. Cargo.toml.orig
  6. cargo_embargo.json
  7. LICENSE
  8. METADATA
  9. MODULE_LICENSE_MIT
  10. OWNERS
  11. README.md
README.md

Want

A Futures channel-like utility to signal when a value is wanted.

Futures are supposed to be lazy, and only starting work if Future::poll is called. The same is true of Streams, but when using a channel as a Stream, it can be hard to know if the receiver is ready for the next value.

Put another way, given a (tx, rx) from futures::sync::mpsc::channel(), how can the sender (tx) know when the receiver (rx) actually wants more work to be produced? Just because there is room in the channel buffer doesn't mean the work would be used by the receiver.

This is where something like want comes in. Added to a channel, you can make sure that the tx only creates the message and sends it when the rx has poll() for it, and the buffer was empty.

License

want is provided under the MIT license. See LICENSE.