Merge pull request AsyncHttpClient#412 from carryel/master

Fixed infinite loop of MultipartBodyTest for master branch.

Author: Stephane Landelle

api/src/main/java/org/asynchttpclient/multipart/MultipartBody.java

@@ -81,7 +81,7 @@ public long read(ByteBuffer buffer) throws IOException {
             int maxLength = buffer.remaining();
 
             if (startPart == parts.size() && endWritten) {
-                return overallLength;
+                return -1;
             }
 
             boolean full = false;

api/src/test/java/org/asynchttpclient/multipart/MultipartBodyTest.java

@@ -91,7 +91,7 @@ private static void compareContentLength(final List<Part> parts) {
                 } catch (IOException ie) {
                     Assert.fail("read failure");
                 }
-                if (readBytes >= 0) {
+                if (readBytes > 0) {
                     totalBytes += readBytes;
                 } else {
                     last = true;