docs: protected void appendSerialNumber(GenerationContext context, XtendTypeDeclaration source, JvmGenericType target) {
  		if (!isAppendSerialNumbersEnable(context)) {
  			return;
  		}
  		for (final JvmField field : target.getDeclaredFields()) {
  			if (SERIAL_FIELD_NAME.equals(field.getSimpleName())) {
  				return;
  			}
  		}
  
  		final JvmField field = this.typesFactory.createJvmField();
  		field.setSimpleName(SERIAL_FIELD_NAME);
  		field.setVisibility(JvmVisibility.PRIVATE);
  		field.setStatic(true);
  		field.setTransient(false);
  		field.setVolatile(false);
  		field.setFinal(true);
  		target.getMembers().add(field);
  		field.setType(this.typeBuilder.cloneWithProxies(this._typeReferenceBuilder.typeRef(long.class)));
  		final long serial = context.getSerial();
  		this.typeBuilder.setInitializer(field, toStringConcatenation(serial + "L")); //$NON-NLS-1$
  		appendGeneratedAnnotation(field, context);
  		this.readAndWriteTracking.markInitialized(field, null);
  	}