Function identify_user_by_alias 

pub async fn identify_user_by_alias(
    configuration: &Configuration,
    app_id: &str,
    alias_label: &str,
    alias_id: &str,
    user_identity_request_body: UserIdentityRequestBody,
) -> Result<InlineResponse200, Error<IdentifyUserByAliasError>>

Upserts one or more Aliases to an existing User identified by (:alias_label, :alias_id).