title: fetch header values from ag-grid in selenium
body: <p>in my website, i have an ag-grid and it loads data only on scrolling; how to get the whole header value and assert it?</p>
  
  <p>i have tried as below and it is working fine for page 1 and i will get new headers once i scroll. how to get the second part of headers?</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>String[] expectedCol={"Subject","Date Received","Status","Tag","Assigned To","Sender Name","Receiver Name"};
           List&lt;WebElement&gt; column=drvobj.findElements(By.xpath("//div [@class='ag-header-cell ag-header-cell-sortable']"));
              for (int i=0;i&lt;column.size();i++)
                  for (int j=0;j&lt;expectedCol.length;j++){
                      System.out.println(column.get(i).getText());
                      System.out.println(expectedCol[j]);
                      if(column.get(i).getText().equals(expectedCol[j])){
                          System.out.println("Text Matched");
                      }
                      else{
                          System.out.println("Text Not Matched");
                      }
                      i++;
                  }</code></pre>
  </div>
  </div>
  </p>