Add bit more commentary on README wrt buffering

Author: cowtowncoder

README.md

@@ -29,7 +29,9 @@ Then in your code you can simply do ([Javadoc](http://sonatype.github.com/async-
     Response r = f.get();
 ```
 
-You can also accomplish asynchronous operation without using a Future if you want to receive and process the response in your handler:
+Note that in this case all the content must be read fully in memory, even if you used `getResponseBodyAsStream()' method on returned `Response` object.
+
+You can also accomplish asynchronous (non-blocking) operation without using a Future if you want to receive and process the response in your handler:
 
 ```java
     import com.ning.http.client.*;
@@ -52,6 +54,8 @@ You can also accomplish asynchronous operation without using a Future if you wan
     });
 ```
 
+(this will also fully read `Response` in memory before calling `onCompleted`)
+
 You can also mix Future with AsyncHandler to only retrieve part of the asynchronous response
 
 ```java
@@ -74,9 +78,11 @@ You can also mix Future with AsyncHandler to only retrieve part of the asynchron
         }
     });
 
-    int statuѕCode = f.get();
+    int statusCode = f.get();
 ```
 
+which is something you want to do for large responses: this way you can process content as soon as it becomes available, piece by piece, without having to buffer it all in memory.
+
  You have full control on the Response life cycle, so you can decide at any moment to stop processing what the server is sending back:
 
 ```java
@@ -85,14 +91,16 @@ You can also mix Future with AsyncHandler to only retrieve part of the asynchron
 
       AsyncHttpClient c = new AsyncHttpClient();
       Future<String> f = c.prepareGet("http://www.ning.com/ ").execute(new AsyncHandler<String>() {
-          private StringBuilder builder = new StringBuilder();
+          private ByteArrayOutputStream bytes = new ByteArrayOutputStream();
 
           @Override
           public STATE onStatusReceived(HttpResponseStatus status) throws Exception {
               int statusCode = status.getStatusCode();
-               // The Status have been read
-               // If you don't want to read the headers,body or stop processing the response
-               return STATE.ABORT;
+              // The Status have been read
+              // If you don't want to read the headers,body or stop processing the response
+              if (statusCode >= 500) {
+                  return STATE.ABORT;
+              }
           }
 
           @Override
@@ -105,15 +113,16 @@ You can also mix Future with AsyncHandler to only retrieve part of the asynchron
 
           @Override
           public STATE onBodyPartReceived(HttpResponseBodyPart bodyPart) throws Exception {
-               builder.append(new String(bodyPart.getBodyPartBytes()));
+               bytes.write(bodyPart.getBodyPartBytes());
                return STATE.CONTINUE
           }
 
           @Override
           public String onCompleted() throws Exception {
                // Will be invoked once the response has been fully read or a ResponseComplete exception
                // has been thrown.
-               return builder.toString();
+               // NOTE: should probably use Content-Encoding from headers
+               return bytes.toString("UTF-8");
           }
 
           @Override