### Question:
SimpleInputBufferPooledObjectOps implements PooledObjectOps<SimpleInputBuffer> { @Override public Supplier<String> createMetricsSupplier() { return () -> null; } SimpleInputBufferPooledObjectOps(ByteBufferAllocator byteBufAllocator, int bufferSizeInBytes); @Override ItemSource<SimpleInputBuffer> createItemSource(ReleaseCallback<SimpleInputBuffer> releaseCallback); @Override void reset(ItemSource<SimpleInputBuffer> pooled); @Override boolean purge(ItemSource<SimpleInputBuffer> pooled); @Override Supplier<String> createMetricsSupplier();  }### Answer:
@Test public void metricsSupplierReturnsNull() { SimpleInputBufferPooledObjectOps ops = new SimpleInputBufferPooledObjectOps( HeapByteBufferAllocator.INSTANCE, TEST_BUFFER_SIZE ); Supplier<String> metricsSupplier = ops.createMetricsSupplier(); String result = metricsSupplier.get(); assertNull(result); }