Snap for 12349386 from 32a1b75548d368cc9900c9dfedb208fa4e9c0167 to sdk-release

Change-Id: Ib1cb121db5f4655f3cf4f98b6d14443ccf675db2
tree: 5efb3af62b3b26df1784dde5e4973853f0dfeae6
  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.