default <E> E attach(Class<E> extensionType, HandleSupplier handleSupplier) {
        throw new UnsupportedOperationException("Virtual factories do not support attach()");
    }
Attaches an extension type. This method is not called if {@link #getFactoryFlags()} contains {@link FactoryFlag#NON_VIRTUAL_FACTORY}.

@param extensionType  The extension type
@param handleSupplier Supplies the database handle. This supplier may lazily open a Handle on the first
                      invocation. Extension implementors should take care not to fetch the handle before it is
                      needed, to avoid opening handles unnecessarily
@param <E>            the extension type
@return An extension of the given type, attached to the given handle
@throws IllegalArgumentException if the extension type is not supported by this factory
@see org.jdbi.v3.core.Jdbi#onDemand(Class)
core/src/main/java/org/jdbi/v3/core/extension/ExtensionFactory.java