#65: Delete memory mapped buffer on close

Unfortunately, the current solution requires a garbage collect to have been performed before the issue is resolved.
Other fixes required either a Java 8 Cleaner.clean() call not accessible from Java 21, or a Java 20 Arena.close(), which is not been finalized in Java 21.

src/main/java/com/riscure/trs/TraceSet.java

@@ -338,6 +338,7 @@ private void checkValid(Trace trace) {
     }
 
     private void closeReader() throws IOException {
+        buffer = null;
         readStream.close();
     }
 

src/test/java/TestTraceSet.java

@@ -675,6 +675,11 @@ void testFileReleasing() throws IOException, TRSFormatException, InterruptedExce
         try (TraceSet traceSet = TraceSet.open(filePath)) {
             traceSet.getMetaData().getTraceSetParameters();
         }
+        // Unfortunately, the current solution requires a garbage collect to have been performed before the issue is resolved.
+        // Other fixes required either a Java 8 Cleaner.clean() call not accessible from Java 21, or a Java 20 Arena.close(),
+        // which is not been finalized in Java 21.
+        System.gc();
+        Thread.sleep(1000);
         // Assert that the opened file has been closed again, by deleting it.
         File file = new File(filePath);
         assert(file.delete());