Document how to alter a solarium edismax query in a hook

We are using SOLR 6.6 and I just tried updating from search_api_solr 1.x to the new 2.0 branch.

In our hook_search_api_solr_query_alter() function we add several boosts using code like the following:

    /** @var \Solarium\Component\EdisMax $edismax */
    $edismax = $solarium_query->getEDisMax();

    $boost_queries['ss_title_exact'] = [
      'query' => "ss_title_exact:\"$query_value\"^11.0",
    ];
    $edismax->addBoostQueries($boost_queries);

    $boost_functions = 'recip(abs(ms(NOW/HOUR,ds_node_display_date)),3.16e-11,1,.4)^3';
    $edismax->setBoostFunctions($boost_functions);

However, these no longer seem to work. I don't know if Solarium 4 has changed how this works, but the functions we are calling all still seem to be valid. But search_api_solr seems to completely these query changes now.

Is this a bug in the new search_api_solr or something I'm doing the wrong way? If so, how do I add boost functions in the new version?