@Test
    public void testUnmap() throws Exception {
        File file = TestUtils.tempFile();
        try (FileChannel channel = FileChannel.open(file.toPath())) {
            MappedByteBuffer map = channel.map(FileChannel.MapMode.READ_ONLY, 0, 0);
            ByteBufferUnmapper.unmap(file.getAbsolutePath(), map);
        }
    }
Checks that unmap doesn't throw exceptions.
clients/src/test/java/org/apache/kafka/common/utils/ByteBufferUnmapperTest.java