Clear Utf8ByteBufCharsetDecoder#splitCharBuffer once char is complete, close AsyncHttpClient#1357

Motivation:

When multiple non US-ASCII chars are split over several chunks,
Utf8ByteBufCharsetDecoder crashes with BufferOverflowException.

This happens because we don't clear the splitCharBuffer in-between and
only do so once decoding is done.

Modifications:

Clear Utf8ByteBufCharsetDecoder#splitCharBuffer once char is complete

Result:

No more BufferOverflowException

Author: slandelle

netty-utils/src/main/java/org/asynchttpclient/netty/util/Utf8ByteBufCharsetDecoder.java

@@ -116,12 +116,13 @@ private void handleSplitCharBuffer(ByteBuffer nioBuffer, boolean endOfInput) thr
             if (res.isError()) {
                 res.throwException();
             }
+            splitCharBuffer.clear();
         }
     }
 
     protected void decodePartial(ByteBuffer nioBuffer, boolean endOfInput) throws CharacterCodingException {
         // deal with pending splitCharBuffer
-        if (splitCharBuffer != null && splitCharBuffer.position() > 0 && nioBuffer.hasRemaining()) {
+        if (splitCharBuffer.position() > 0 && nioBuffer.hasRemaining()) {
             handleSplitCharBuffer(nioBuffer, endOfInput);
         }
 

netty-utils/src/test/java/org/asynchttpclient/netty/util/ByteBufUtilsTest.java renamed to netty-utils/src/test/java/org/asynchttpclient/netty/util/Utf8ByteBufCharsetDecoderTest.java

@@ -20,7 +20,7 @@
 
 import org.testng.annotations.Test;
 
-public class ByteBufUtilsTest {
+public class Utf8ByteBufCharsetDecoderTest {
 
     @Test
     public void testByteBuf2BytesHasBackingArray() {