byte[] pollEntryBytes() throws IOException, InterruptedException {
        return pollEntryBytes(100);
    }
@Test
    public void testReaderWithBlockInternalFragmentation() throws IOException, InterruptedException {
        writeSegmentWithFirstBlockContainingInternalFragmentation();

        try (DeadLetterQueueReader reader = new DeadLetterQueueReader(dir)) {
            byte[] rawStr = reader.pollEntryBytes();
            assertNotNull(rawStr);
            assertEquals(stringOf(INTERNAL_FRAG_PAYLOAD_SIZE, 'A'), new String(rawStr, StandardCharsets.UTF_8));

            rawStr = reader.pollEntryBytes();
            assertNotNull(rawStr);
            assertEquals("BBBBBBBBBB", new String(rawStr, StandardCharsets.UTF_8));
        }
    }