docs: public com.squareup.okhttp.Call postUiOpenwindowNewmailAsync(String datasource, String token, UiNewMail uiNewMail,
              final ApiCallback<Void> callback) throws ApiException {
  
          com.squareup.okhttp.Call call = postUiOpenwindowNewmailValidateBeforeCall(datasource, token, uiNewMail,
                  callback);
          apiClient.executeAsync(call, callback);
          return call;
      }