gate.HeaderDelegate</code></a> if one
 is available via <a href="../ext/RuntimeDelegate.html#createHeaderDelegate(java.lang.Class)"><code>RuntimeDelegate.createHeaderDelegate(java.lang.Class)</code></a> for the header value
 class or using its <code>toString</code> method if a header delegate is not available.

 <p>
 For example: <code>containsHeaderString("cache-control", "no-store"::equalsIgnoreCase)</code> will return <code>true</code> if
 a <code>Cache-Control</code> header exists that has the value <co