Update the README. (#17)

README.md

@@ -1,15 +1,93 @@
 Contains utility classes in the style of `dart:async` to work with asynchronous
 computations.
 
-### Zipping streams
+* The [`AsyncCache`][AsyncCache] class allows expensive asynchronous
+  computations values to be cached for a period of time.
 
-The `StreamZip` class can combine several streams of events into a single stream
-of tuples of events.
+* The [`AsyncMemoizer`][AsyncMemoizer] class makes it easy to only run an
+  asynchronous operation once on demand.
 
-### Results
+* The [`CancelableOperation`][CancelableOperation] class defines an operation
+  that can be canceled by its consumer. The producer can then listen for this
+  cancellation and stop producing the future when it's received. It can be
+  created using a [`CancelableCompleter`][CancelableCompleter].
 
-The package introduces a `Result` class that can hold either a value or an
-error. It allows capturing an asynchronous computation which can give either a
-value or an error, into an asynchronous computation that always gives a `Result`
-value, where errors can be treated as data. It also allows releasing the
-`Result` back into an asynchronous computation.
+* The delegating wrapper classes allow users to easily add functionality on top
+  of existing instances of core types from `dart:async`. These include
+  [`DelegatingFuture`][DelegatingFuture],
+  [`DelegatingStream`][DelegatingStream],
+  [`DelegatingStreamSubscription`][DelegatingStreamSubscription],
+  [`DelegatingStreamConsumer`][DelegatingStreamConsumer],
+  [`DelegatingSink`][DelegatingSink],
+  [`DelegatingEventSink`][DelegatingEventSink], and
+  [`DelegatingStreamSink`][DelegatingStreamSink].
+
+  The delegating classes all have `.typed()` constructors which allow users to
+  cast the generic type parameters in a way that's safe for strong mode. For
+  example, if `future` is a `Future<dynamic>` and you know it actually contains an
+  `int`, you can write `DelegatingFuture.typed<int>(future)`.
+
+* The [`FutureGroup`][FutureGroup] class makes it easy to wait until a group of
+  features that may change over time completes.
+
+* The [`LazyStream`][LazyStream] class allows a stream to be initialized lazily
+  when `.listen()` is first called.
+
+* The [`NullStreamSink`][NullStreamSink] class is an implementation of
+  `StreamSink` that discards all events.
+
+* The [`RestartableTimer`][RestartableTimer] class extends `Timer` with a
+  `reset()` method.
+
+* The [`Result`][Result] class that can hold either a value or an error. It
+  provides various utilities for converting to and from `Future`s and `Stream`s.
+
+* The [`StreamGroup`][StreamGroup] class merges a collection of streams into a
+  single output stream.
+
+* The [`StreamQueue`][StreamQueue] class allows a stream to be consumed
+  event-by-event rather than being pushed whichever events as soon as they
+  arrive.
+
+* The [`StreamSplitter`][StreamSplitter] class allows a stream to be duplicated
+  into multiple identical streams.
+
+* The [`StreamZip`][StreamZip] class combines multiple streams into a single
+  stream of lists of events.
+
+* This package contains a number of [`StreamTransformer`][StreamTransformer]s.
+  [`SingleSubscriptionTransformer`][SingleSubscriptionTransformer] converts a
+  broadcast stream to a single-subscription stream, and
+  [`typedStreamTransformer`][typedStreamTransformer] casts the type of a
+  `Stream`. It also defines a transformer type for [`StreamSink`][StreamSink]s,
+  [`StreamSinkTransformer`][StreamSinkTransformer].
+
+* The [`SubscriptionStream`][SubscriptionStream] class wraps a
+  `StreamSubscription` so it can be re-used as a `Stream`.
+
+[AsyncCache]: https://www.dartdocs.org/documentation/async/latest/async/AsyncCache-class.html
+[AsyncMemoizer]: https://www.dartdocs.org/documentation/async/latest/async/AsyncMemoizer-class.html
+[CancelableCompleter]: https://www.dartdocs.org/documentation/async/latest/async/CancelableCompleter-class.html
+[CancelableOperation]: https://www.dartdocs.org/documentation/async/latest/async/CancelableOperation-class.html
+[DelegatingEventSink]: https://www.dartdocs.org/documentation/async/latest/async/DelegatingEventSink-class.html
+[DelegatingFuture]: https://www.dartdocs.org/documentation/async/latest/async/DelegatingFuture-class.html
+[DelegatingSink]: https://www.dartdocs.org/documentation/async/latest/async/DelegatingSink-class.html
+[DelegatingStreamConsumer]: https://www.dartdocs.org/documentation/async/latest/async/DelegatingStreamConsumer-class.html
+[DelegatingStreamSink]: https://www.dartdocs.org/documentation/async/latest/async/DelegatingStreamSink-class.html
+[DelegatingStreamSubscription]: https://www.dartdocs.org/documentation/async/latest/async/DelegatingStreamSubscription-class.html
+[DelegatingStream]: https://www.dartdocs.org/documentation/async/latest/async/DelegatingStream-class.html
+[FutureGroup]: https://www.dartdocs.org/documentation/async/latest/async/FutureGroup-class.html
+[LazyStream]: https://www.dartdocs.org/documentation/async/latest/async/LazyStream-class.html
+[NullStreamSink]: https://www.dartdocs.org/documentation/async/latest/async/NullStreamSink-class.html
+[RestartableTimer]: https://www.dartdocs.org/documentation/async/latest/async/RestartableTimer-class.html
+[Result]: https://www.dartdocs.org/documentation/async/latest/async/Result-class.html
+[SingleSubscriptionTransformer]: https://www.dartdocs.org/documentation/async/latest/async/SingleSubscriptionTransformer-class.html
+[StreamGroup]: https://www.dartdocs.org/documentation/async/latest/async/StreamGroup-class.html
+[StreamQueue]: https://www.dartdocs.org/documentation/async/latest/async/StreamQueue-class.html
+[StreamSinkTransformer]: https://www.dartdocs.org/documentation/async/latest/async/StreamSinkTransformer-class.html
+[StreamSink]: https://api.dartlang.org/stable/latest/dart-async/StreamSink-class.html
+[StreamSplitter]: https://www.dartdocs.org/documentation/async/latest/async/StreamSplitter-class.html
+[StreamTransformer]: https://api.dartlang.org/stable/latest/dart-async/StreamTransformer-class.html
+[StreamZip]: https://www.dartdocs.org/documentation/async/latest/async/StreamZip-class.html
+[SubscriptionStream]: https://www.dartdocs.org/documentation/async/latest/async/SubscriptionStream-class.html
+[typedStreamTransformer]: https://www.dartdocs.org/documentation/async/latest/async/typedStreamTransformer.html