Updated README.md file (#115)

isolate_example/README.md

@@ -9,6 +9,31 @@ A sample application that demonstrate best practices when using [`isolates`](htt
 * Demonstrate how to initialize and use an isolate.
 * Show the cost of moving data between isolates and provide alternatives.
 
+## The important bits
+
+### `page_one.dart`
+
+Compares running a large computation on the main isolate with running the same calculation
+on a second isolate. When the main isolate is used, Flutter is unable to render new frames, and
+the `SmoothAnimationWidget`'s animation freezes.
+### `page_two.dart`
+
+Creates an isolate used to run an infinite loop that sums batches of 100M randomly generated
+numbers at a time. Users can start, terminate, pause, and resume the isolate, as well as modify
+how the calculation is performed.
+
+### `page_three.dart`
+
+Demonstrates how expensive it is to move large amounts of data between isolates and a 
+better alternative to move data. This page creates an isolate that can add up a list of numbers
+and gives users three options for how to provide it with input:
+
+* Send values normally using a List
+* Send the values using TransferableTypedData
+* Generate the values on the second isolate, so no copying is necessary
+
+Users can then compare the performance of each approach using the displayed timestamps.
+
 ## Questions/issues
 
 If you have a general question about any of the techniques you see in
@@ -19,4 +44,4 @@ the sample, the best places to go are:
 * [StackOverflow](https://stackoverflow.com/questions/tagged/flutter)
 
 If you run into an issue with the sample itself, please file an issue
-in the [main Flutter repo](https://github.com/flutter/flutter/issues).
+in the [main Flutter repo](https://github.com/flutter/flutter/issues).