PartNumber          int                 // only useful in case of GetObject/HeadObject
	CheckPrecondFn      CheckPreconditionFn // only set during GetObject/HeadObject/CopyObjectPart preconditional valuation
	EvalMetadataFn      EvalMetadataFn      // only set for retention settings, meant to be used only when updating metadata in-place.

// -----------
// The HEAD operation retrieves metadata from an object without returning the object itself.
func (api objectAPIHandlers) HeadObjectHandler(w http.ResponseWriter, r *http.Request) {
	ctx := newContext(r, w, "HeadObject")
	defer logger.AuditLog(ctx, w, r, mustGetClaimsFromToken(r))

	objectAPI := api.ObjectAPI()
	if objectAPI == nil {
		writeErrorResponseHeadersOnly(w, errorCodes.ToAPIErr(ErrServerNotInitialized))
		return

            ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
            ObjectInputStream ois = new ObjectInputStream(bais);
            CrawlerStatus deserialized = (CrawlerStatus) ois.readObject();
            ois.close();

            // Verify - enum instances are singletons
            assertSame(original, deserialized);
            assertEquals(original.name(), deserialized.name());

        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
        ObjectInputStream ois = new ObjectInputStream(bais);
        TestAbstractRule deserializedRule = (TestAbstractRule) ois.readObject();
        ois.close();

        // Verify
        assertEquals("serializeRule", deserializedRule.getRuleId());
        assertNotNull(deserializedRule.getResponseProcessor());

        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
        ObjectInputStream ois = new ObjectInputStream(bais);
        CrawlerSystemException deserialized = (CrawlerSystemException) ois.readObject();
        ois.close();

        // Verify
        assertNotNull(deserialized);
        assertEquals(original.getMessage(), deserialized.getMessage());
        assertNotNull(deserialized.getCause());

        // Deserialize
        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
        ObjectInputStream ois = new ObjectInputStream(bais);
        TestRule deserializedRule = (TestRule) ois.readObject();
        ois.close();

        // Verify
        assertEquals(originalRule.getRuleId(), deserializedRule.getRuleId());
        assertNotNull(deserializedRule.getResponseProcessor());

        ObjectInputStream ois = new ObjectInputStream(bais);
        @SuppressWarnings("unchecked")
        TestAccessResultData<String> deserialized = (TestAccessResultData<String>) ois.readObject();
        ois.close();

        // Verify
        assertEquals("test data", new String(deserialized.getData()));
        assertNotNull(deserialized.getData());
    }

    /**