Fix a potential fd leak in AbstractDiskHttpData.getChunk (#10270)

Motivation:

`FileChannel.read()` may throw an IOException. We must deal with this in case of the occurrence of `I/O` error.

Modification:

Place the `FileChannel.read()` method call in the `try-finally` block.

Result:

Advoid fd leak.


Co-authored-by: Norman Maurer <norman_maurer@apple.com>

codec-http/src/main/java/io/netty/handler/codec/http/multipart/AbstractDiskHttpData.java

@@ -295,15 +295,17 @@ public abstract class AbstractDiskHttpData extends AbstractHttpData {
         }
         int read = 0;
         ByteBuffer byteBuffer = ByteBuffer.allocate(length);
+        try {
             while (read < length) {
                 int readnow = fileChannel.read(byteBuffer);
                 if (readnow == -1) {
-                fileChannel.close();
-                fileChannel = null;
                     break;
-            } else {
+                }
                 read += readnow;
             }
+        } finally {
+            fileChannel.close();
+            fileChannel = null;
         }
         if (read == 0) {
             return EMPTY_BUFFER;