Crate futures

Abstractions for asynchronous programming.

This crate provides a number of core abstractions for writing asynchronous code:

• Futures are single eventual values produced by asychronous computations. Some programming languages (e.g. JavaScript) call this concept "promise".
• Streams represent a series of values produced asynchronously.
• Sinks provide support for asynchronous writing of data.
• Executors are responsible for running asynchronous tasks.

The crate also contains abstractions for asynchronous I/O and cross-task communication.

Underlying all of this is the task system, which is a form of lightweight threading. Large asynchronous computations are built up using futures, streams and sinks, and then spawned as independent tasks that are run to completion, but do not block the thread running them.

Modules

channel	Cross-task communication.
executor	Task execution.
future	Asynchronous values.
io	Asynchronous I/O.
prelude	A "prelude" for crates using the futures crate.
sink	Asynchronous sinks.
stream	Asynchronous streams.
task	Tools for working with tasks.

Macros

join	Polls multiple futures simultaneously, returning a tuple of all results once complete.
pending	A macro which yields to the event loop once.
poll	A macro which returns the result of polling a future once within the current async context.
ready	Extracts the successful type of a Poll<T>.
select	Polls multiple futures simultaneously, executing the branch for the future that finishes first.
spawn	Spawns a task onto the context's executor that polls the given future with output () to completion.
spawn_with_handle	Spawns a task onto the context's executor that polls the given future to completion and returns a future that resolves to the spawned future's output.
try_join	Polls multiple futures simultaneously, resolving to a Result containing either a tuple of the successful outputs or an error.
try_poll	Extracts Poll<T> from Poll<Result<T, E>>.
try_ready	Extracts the successful type of a Poll<Result<T, E>>.