code: public JSONObject searchInFacetValues(String facetName, String facetQuery, Query params, RequestOptions requestOptions) throws AlgoliaException {
      params = params == null ? new Query() : params;
      String paramsString = params.setFacetQuery(facetQuery).getQueryString();
      JSONObject body = new JSONObject();
      String encodedFacetName;
      try {
        encodedFacetName = URLEncoder.encode(facetName, "UTF-8");
        body.put("params", paramsString);
      } catch (JSONException e) {
        throw new RuntimeException(e);
      } catch (UnsupportedEncodingException e) {
        throw new RuntimeException(e);
      }
      return client.postRequest("/1/indexes/" + encodedIndexName + "/facets/" + encodedFacetName + "/query", body.toString(), false, true, requestOptions);
    }
docs: Search into a facet value
  
  @param requestOptions Options to pass to this request