private void verifyRefCnts(List<HttpContent> httpContents) {
    for (HttpContent httpContent : httpContents) {
      assertEquals("Reference count of http content has changed", 1, httpContent.refCnt());
    }
  }
Verifies that the reference counts of {@code httpContents} is undisturbed after all operations.
@param httpContents the {@link List<HttpContent>} of contents whose reference counts need to checked.
ambry-rest/src/test/java/com/github/ambry/rest/NettyRequestTest.java