Storefront API - Search by product variant

[mnf]

The Admin API has a field in the QueryRoot called productVariant with an id argument (https://shopify.dev/docs/admin-api/graphql/reference/common-objects/queryroot/index).  The Storefront API does not have this field on the QueryRoot.  How can I search for a product variant on the storefront api in a similar way as the admin api (by the id or even sku would work)?