Clarify use of buffered channel in the timeouts example.

The buffered channel prevents goroutine leaks in case the
channel doesn't end up being read (as indeed happens to c1).

Updates #207

examples/timeouts/timeouts.go

@@ -12,7 +12,10 @@ func main() {
 
 	// For our example, suppose we're executing an external
 	// call that returns its result on a channel `c1`
-	// after 2s.
+	// after 2s. Note that the channel is buffered, so the
+	// send in the goroutine is nonblocking. This is a
+	// common pattern to prevent goroutine leaks in case the
+	// channel is never read.
 	c1 := make(chan string, 1)
 	go func() {
 		time.Sleep(2 * time.Second)

examples/timeouts/timeouts.hash

@@ -1,2 +1,2 @@
-93343e1aacb14f818c87732914c29ba57afab245
-MgcfA-xpJO9
+b1e8d0efbabd0c52271a85fad5ad58dcd1c7c476
+gyY_qDsRVUe

public/timeouts

@@ -44,7 +44,7 @@ elegant thanks to channels and <code>select</code>.</p>
             
           </td>
           <td class="code leading">
-            <a href="http://play.golang.org/p/MgcfA-xpJO9"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
+            <a href="http://play.golang.org/p/gyY_qDsRVUe"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
           <div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
 </pre></div>
 
@@ -80,7 +80,10 @@ elegant thanks to channels and <code>select</code>.</p>
           <td class="docs">
             <p>For our example, suppose we&rsquo;re executing an external
 call that returns its result on a channel <code>c1</code>
-after 2s.</p>
+after 2s. Note that the channel is buffered, so the
+send in the goroutine is nonblocking. This is a
+common pattern to prevent goroutine leaks in case the
+channel is never read.</p>
 
           </td>
           <td class="code leading">